Chore: use relation.identifier for source name quoting check

Author: jnallaliveaction

sqlmesh/dbt/source.py

@@ -82,9 +82,8 @@ def canonical_name(self, context: DbtContext) -> str:
                     f"'source' macro failed for '{self.config_name}' with exception '{e}'."
                 )
 
-            needs_identifier_quoting = bool(
-                self.table_name and ("." in self.table_name or " " in self.table_name)
-            )
+            identifier = relation.identifier or ""
+            needs_identifier_quoting = "." in identifier or " " in identifier
             relation = relation.quote(
                 database=False,
                 schema=False,