Add a downgrade step from 6 to 5 to detect new delete blocks

[hudi-bot]

In table version 6, we introduce a new delete block format (v3) with Avro serde (HUDI-5760).  For downgrading a table from v6 to v5, we need to perform compaction to handle v3 delete blocks created using the new format.
Also with the addition of record index field in Metadata table schema, the downgrade needs to delete the metadata table to avoid column drop errors after downgrade.

JIRA info

• Link: https://issues.apache.org/jira/browse/HUDI-6621
• Type: Improvement
• Fix version(s):
  • 1.1.0

[hudi-bot]

Linked PR(s)

• [HUDI-6621] Fix downgrade handler for 0.14.0 #9467