Add region tags & cleanup ADK Sample

[psx95]

• Adds region tags.
• Removes extraneous span generation.
• Removes unused imports.

[snippet-bot]

Here is the summary of changes.

You are about to add 1 region tag.

• samples/adk-sql-agent/main.py:106, tag opentelemetry_adk_launch_web_interface

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[aabmass]

Discussed changes offline