Fix double backtick wrapping in setCatalog and setSchema (#1454)

## Description

When catalog or schema names were passed already wrapped in backticks,
setCatalog/setSchema would produce invalid SQL like
```
 SET CATALOG ``name``
```
Strip existing backticks before wrapping and before storing, so
getCatalog/ getSchema always return the bare identifier name.

## Testing

The changes are covered by unit tests.

## Additional Notes to the Reviewer

This fixes #1453 and restores compatibility with v2 of the jdbc driver:
it also allowed "pre-quoted" identifiers and handled them correctly.

Signed-off-by: Dan Homola <dan.homola@hotmail.cz>
Co-authored-by: Gopal Lal <135012033+gopalldb@users.noreply.github.com>

Author: no23reason

NEXT_CHANGELOG.md

@@ -7,7 +7,8 @@
 ### Updated
 
 ### Fixed
+- Fixed `setCatalog()` and `setSchema()` producing invalid SQL (e.g. `SET CATALOG ``name``) when the catalog or schema name was passed already wrapped in backticks. Backticks are now stripped before wrapping, and `getCatalog()`/`getSchema()` return the bare identifier name.
 
 ---
 *Note: When making changes, please add your change under the appropriate section
-with a brief description.*
+with a brief description.*

src/main/java/com/databricks/jdbc/api/impl/DatabricksConnection.java

@@ -489,8 +489,9 @@ public void setCatalog(String catalog) throws SQLException {
       return;
     }
     Statement statement = this.createStatement();
-    statement.execute("SET CATALOG `" + catalog + "`");
-    this.session.setCatalog(catalog);
+    String cleanCatalog = stripBackticks(catalog);
+    statement.execute("SET CATALOG `" + cleanCatalog + "`");
+    this.session.setCatalog(cleanCatalog);
   }
 
   @Override
@@ -865,8 +866,9 @@ public Struct createStruct(String typeName, Object[] attributes) throws SQLExcep
   @Override
   public void setSchema(String schema) throws SQLException {
     Statement statement = this.createStatement();
-    statement.execute("USE SCHEMA `" + schema + "`");
-    session.setSchema(schema);
+    String cleanSchema = stripBackticks(schema);
+    statement.execute("USE SCHEMA `" + cleanSchema + "`");
+    session.setSchema(cleanSchema);
   }
 
   @Override
@@ -1090,4 +1092,14 @@ private void closeStatementSafely(Statement statement) {
       }
     }
   }
+
+  private static String stripBackticks(String identifier) {
+    if (identifier != null
+        && identifier.startsWith("`")
+        && identifier.endsWith("`")
+        && identifier.length() >= 2) {
+      return identifier.substring(1, identifier.length() - 1);
+    }
+    return identifier;
+  }
 }

src/test/java/com/databricks/jdbc/api/impl/DatabricksConnectionTest.java

@@ -134,6 +134,60 @@ public void testGetAndSetSchemaAndCatalog() throws SQLException {
     assertEquals(connection.getSchema(), DEFAULT_SCHEMA);
   }
 
+  @Test
+  public void testSetCatalogAndSchemaWithPreWrappedBackticks() throws SQLException {
+    when(databricksClient.createSession(
+            new Warehouse(WAREHOUSE_ID), CATALOG, SCHEMA, new HashMap<>()))
+        .thenReturn(IMMUTABLE_SESSION_INFO);
+    connection = new DatabricksConnection(connectionContext, databricksClient);
+    connection.open();
+
+    String backtickWrappedCatalog = "`catalog-with-hyphen`";
+    when(databricksClient.executeStatement(
+            eq("SET CATALOG `catalog-with-hyphen`"),
+            eq(new Warehouse(WAREHOUSE_ID)),
+            eq(new HashMap<>()),
+            eq(StatementType.SQL),
+            any(),
+            any(),
+            any()))
+        .thenReturn(resultSet);
+    connection.setCatalog(backtickWrappedCatalog);
+    assertEquals(connection.getCatalog(), "catalog-with-hyphen");
+
+    String backtickWrappedSchema = "`schema-with-hyphen`";
+    when(databricksClient.executeStatement(
+            eq("USE SCHEMA `schema-with-hyphen`"),
+            eq(new Warehouse(WAREHOUSE_ID)),
+            eq(new HashMap<>()),
+            eq(StatementType.SQL),
+            any(),
+            any(),
+            any()))
+        .thenReturn(resultSet);
+    connection.setSchema(backtickWrappedSchema);
+    assertEquals(connection.getSchema(), "schema-with-hyphen");
+
+    verify(databricksClient)
+        .executeStatement(
+            eq("SET CATALOG `catalog-with-hyphen`"),
+            eq(new Warehouse(WAREHOUSE_ID)),
+            eq(new HashMap<>()),
+            eq(StatementType.SQL),
+            any(),
+            any(),
+            any());
+    verify(databricksClient)
+        .executeStatement(
+            eq("USE SCHEMA `schema-with-hyphen`"),
+            eq(new Warehouse(WAREHOUSE_ID)),
+            eq(new HashMap<>()),
+            eq(StatementType.SQL),
+            any(),
+            any(),
+            any());
+  }
+
   @Test
   public void testSetCatalogAndSchemaWithHyphenatedIdentifiers() throws SQLException {
     when(databricksClient.createSession(