[HUDI-3432] Fixing restore with metadata enabled

[nsivabalan]

What is the purpose of the pull request

• Found couple of issues while testing restore w/ metadata enabled (COW and MOR table).
• avro schema for metadata payload did not have default set to null for colsStats and bloomFilterMetadata that got added recently. Was running into issues with avro deserialization.
• While reading logs for metadata table, partition name was not set with MergedLogRecordScanner. Have created a follow ticket to chase all such code paths and fix.

Verify this pull request

• Tested restore for COW and MOR table for few scenarios. restore succeeded and validated the table after restore to ensure table record count matched the restored commit.

Committer checklist

• Has a corresponding JIRA in PR title & commit

• Commit message is descriptive of the change

• CI is green

• Necessary doc changes done or have another open PR

• For large changes, please consider breaking it into sub-tasks under an umbrella JIRA.

[hudi-bot]

CI report:

• 096efd8 Azure: SUCCESS

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