[HUDI-19878] Initialize Spark context for record index deletion

[txwyy123]

What is the problem?

metadata delete-record-index constructs a HoodieSparkEngineContext from the command's Spark context, but does not initialize that context first. When this is the first metadata command executed in a CLI session, the context is null and the command fails with a NullPointerException.

What does this change do?

• Add the standard --sparkMaster option used by the other Spark-backed metadata commands.
• Initialize the command's Spark context before deleting the Record Index partition.
• Add a regression test that invokes the command on a fresh MetadataCommand instance and verifies the Record Index partition is removed.

This is the smallest targeted fix: it reuses the existing lazy initialization helper and leaves the metadata deletion behavior unchanged.

Fixes #19878

Testing

• mvn -P spark3.5 -Dtest=TestMetadataCommand#testMetadataDeleteRecordIndexInitializesSparkContext -Dsurefire.failIfNoSpecifiedTests=false -Dcheckstyle.skip=true -Dspotless.check.skip=true -Drat.skip=true test
• mvn -P spark3.5 -Dtest=TestMetadataCommand -Dsurefire.failIfNoSpecifiedTests=false -Dcheckstyle.skip=true -Dspotless.check.skip=true -Drat.skip=true test
• mvn -P spark3.5 -DskipTests -Dspotless.check.skip=true -Drat.skip=true checkstyle:check

[hudi-bot]

CI report:

• f8395c6 Azure: SUCCESS

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[hudi-agent]

⚠️ 🤖 This review was generated by an AI agent and may contain mistakes. Please verify any suggestions before applying.

Thanks for the contribution! This PR fixes a NullPointerException in metadata delete-record-index by adding the --sparkMaster option and lazily initializing the CLI's Spark context before the deletion, matching the pattern already used by the other Spark-backed metadata commands, and adds a regression test on a fresh command instance. No issues flagged from this automated pass — a Hudi committer or PMC member can take it from here for a final review.

cc @yihua