feat: add update metadata step for upgrading candidate region

[WenyXu]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

Add update metadata step for upgrading candidate region.

It sets the candidate peer as the leader_peer and removes the candidate region from follower_peers if any.

Behaviors:

Abort(non-retry):

• TableRoute or RegionRoute is not found.
  Typically, it's impossible, there is no other DDL procedure executed concurrently for the current table.

Retry:

• Failed to update TableRouteValue
• Failed to retrieve the metadata of the table.

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.

Refer to a related PR or issue link (optional)

#2700

[codecov]

Codecov Report

Merging #2811 (30f5c4a) into develop (cce5edc) will decrease coverage by 0.31%.
The diff coverage is 92.81%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2811      +/-   ##
===========================================
- Coverage    84.78%   84.47%   -0.31%     
===========================================
  Files          735      737       +2     
  Lines       115557   115840     +283     
===========================================
- Hits         97974    97860     -114     
- Misses       17583    17980     +397     

[WenyXu]

@MichaelScofield @fengjiachun PTAL