feat(Spanner): integrate SourceConfigParser to centralize shard configuration loading for SourceDbToSpanner pipelines.

[pratickchokhani]

1. Implemented centralize shard configuration loading for SourceDbToSpanner
2. Added integration tests for Astra DB
3. Updated integration tests across the template.

[codecov]

Codecov Report

❌ Patch coverage is 85.41667% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 56.17%. Comparing base (fdf3c92) to head (2d3b2a3).

Files with missing lines	Patch %	Lines
...loud/teleport/v2/templates/PipelineController.java	0.00%	7 Missing ⚠️
...ource/jdbc/AbstractJdbcSrcToSpSourceConnector.java	0.00%	4 Missing ⚠️
...cloud/teleport/v2/templates/SourceDbToSpanner.java	83.33%	1 Missing and 1 partial ⚠️
...rce/cassandra/CassandraSrcToSpSourceConnector.java	50.00%	1 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##               main    #3854       +/-   ##
=============================================
+ Coverage     38.08%   56.17%   +18.08%     
- Complexity      511     7336     +6825     
=============================================
  Files           195     1126      +931     
  Lines         11764    68711    +56947     
  Branches       1179     7778     +6599     
=============================================
+ Hits           4480    38596    +34116     
- Misses         6919    27619    +20700     
- Partials        365     2496     +2131     

Components	Coverage Δ
spanner-templates	87.59% <83.72%> (∅)
spanner-import-export	68.91% <ø> (∅)
spanner-live-forward-migration	89.47% <ø> (∅)
spanner-live-reverse-replication	83.62% <ø> (∅)
spanner-bulk-migration	92.24% <83.72%> (∅)
gcs-spanner-dv	88.79% <ø> (∅)

Files with missing lines	Coverage Δ
...eam/it/gcp/cloudsql/CloudSqlShardOrchestrator.java	85.83% <100.00%> (-0.52%)	⬇️
...ud/teleport/v2/options/OptionsToConfigBuilder.java	92.94% <100.00%> (ø)
...ud/teleport/v2/source/ISrcToSpSourceConnector.java	100.00% <ø> (ø)
...cassandra/iowrapper/CassandraIOWrapperFactory.java	100.00% <100.00%> (ø)
.../cassandra/iowrapper/CassandraIOWrapperHelper.java	100.00% <100.00%> (ø)
...der/io/cassandra/iowrapper/CassandraIoWrapper.java	100.00% <ø> (ø)
...t/v2/source/jdbc/ShardedJdbcDbConfigContainer.java	100.00% <100.00%> (ø)
...urce/jdbc/SingleInstanceJdbcDbConfigContainer.java	100.00% <100.00%> (ø)
...t/v2/source/mysql/MySqlSrcToSpSourceConnector.java	98.85% <100.00%> (ø)
...ource/postgres/PostgresSrcToSpSourceConnector.java	99.00% <100.00%> (ø)
... and 4 more

... and 943 files with indirect coverage changes

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[bharadwaj-aditya]

LGTM

[bharadwaj-aditya]

In the updated flow, the sharded and non-sharded flows are basically the same. Why do we need this special handling ?