fix: use hash to compare user metadata value (#10749)

# Which Problems Are Solved

Depending on the metadata values (already existing), the newly created
index (#10415) cannot be created or error in the future.

# How the Problems Are Solved

- Create the index using `sha256` and change the query to use sha256 as
well when comparing bytes values such as user_metadata.
- Added a setup step to cleanup potentially created index on
`projections.user_metadata5`

# Additional Changes

None

# Additional Context

- relates to #10415 
- requires backport to v4.x

cmd/setup/65.sql

@@ -0,0 +1,3 @@
+ALTER INDEX IF EXISTS projections.user_metadata5_metadata_key_idx
+    RENAME TO user_metadata5_key_idx;
+DROP INDEX IF EXISTS projections.user_metadata5_metadata_value_idx;