Refactor Databricks Agent Phase

[Future-Outlier]

Tracking issue

flyteorg/flyte#3936

Why are the changes needed?

To support more phases in the databricks agent.
At before, we only have RUNNING and terminal phase, which doesn't provide good user experience to users.

What changes were proposed in this pull request?

1. fix bug in bigquery agent
2. Implement the databricks plugin's Status function's logic to decide databricks agent's phase.
   databricks plugin implementation: https://github.com/flyteorg/flyte/blob/master/flyteplugins/go/tasks/plugins/webapi/databricks/plugin.go#L251-L283

How was this patch tested?

1. Unit tests
2. return Initializing Phase, messages and logs to flytepropeller, show messages in the flyteconsole.

Screenshots

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Related PRs

#1797

[codecov]

Codecov Report

Attention: Patch coverage is 93.33333% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 85.99%. Comparing base (1c0b228) to head (7bfd8f5).
Report is 8 commits behind head on master.

Files	Patch %	Lines
...gins/flytekit-spark/flytekitplugins/spark/agent.py	88.88%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2244      +/-   ##
==========================================
- Coverage   85.99%   85.99%   -0.01%     
==========================================
  Files         320      322       +2     
  Lines       24250    24371     +121     
  Branches     3667     3690      +23     
==========================================
+ Hits        20854    20958     +104     
- Misses       2745     2756      +11     
- Partials      651      657       +6     

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