Fix bug where default session is not properly being set + small fixes (#89)

There's a bug where the default session is not being recognized and
we're instead creating a new session and connecting to the
LocalSparkConnectService. We now use a different API to mitigate the
issue

Author: garlandz-db

contrib/templates/scala-job/databricks_template_schema.json

@@ -10,7 +10,7 @@
     },
     "artifacts_dest_path": {
       "type": "string",
-      "description": "\nPlease provide the Volumes destination path in Databricks where the directory will be created containing the JAR and other artifacts to store. [example: /Volumes/abcdef1234567890].\nNote: Your admin must allowlist the Volumes JAR path you specify for your workspace (see https://docs.databricks.com/en/data-governance/unity-catalog/manage-privileges/allowlist.html)",
+      "description": "\nPlease provide the Volumes destination path in Databricks where the directory will be created containing the JAR and other artifacts to store. [example: /Volumes/abcdef1234567890].\nNote: Only when using Standard clusters, your admin must allowlist the Volumes JAR path you specify for your workspace (see https://docs.databricks.com/en/data-governance/unity-catalog/manage-privileges/allowlist.html)",
       "order": 2,
       "pattern": "^/Volumes(?:/[a-z0-9_-]+)+$",
       "pattern_match_failure_message": "Path must be of the form ^/Volumes(?:/[a-z0-9_-]+)+$"

contrib/templates/scala-job/template/{{.project_name}}/src/main/scala/com/examples/Main.scala

@@ -26,7 +26,7 @@ object Main {
     // Get DATABRICKS_RUNTIME_VERSION environment variable
     if (sys.env.contains("DATABRICKS_RUNTIME_VERSION")) {
       println("Running in a Databricks cluster")
-      SparkSession.builder().getOrCreate()
+      SparkSession.active
     } else {
       println("Running outside Databricks")
       DatabricksSession.builder()