optimize: raft mode maintains the reload logic consistent with the file

[funky-eyes]

• I have registered the PR changes.

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

存在于file一样的缺点，reload后会删除failed状态的事务及涉及的分支事务和锁
以及reload时机于file有区别，file是在重启时，而raft是在leader选举后进行reload（一般leader重选举就是leader挂了）

It has the same drawbacks as in the file: after reload, failed transactions, associated branch transactions, and locks will be deleted. Additionally, the timing of the reload differs from that of the file; the file reload occurs during a restart, while the RAFT reload happens after a leader election (usually, the leader re-election occurs when the leader has failed).

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov]

Codecov Report

Attention: Patch coverage is 25.00000% with 18 lines in your changes missing coverage. Please review.

Project coverage is 52.60%. Comparing base (34990eb) to head (b4116c1).
Report is 1 commits behind head on 2.x.

Files with missing lines	Patch %	Lines
...erver/storage/raft/session/RaftSessionManager.java	28.57%	9 Missing and 1 partial ⚠️
...org/apache/seata/server/session/SessionHolder.java	11.11%	8 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x    #7027      +/-   ##
============================================
- Coverage     52.61%   52.60%   -0.02%     
- Complexity     6590     6596       +6     
============================================
  Files          1126     1126              
  Lines         40004    40020      +16     
  Branches       4696     4700       +4     
============================================
+ Hits          21050    21052       +2     
- Misses        16946    16963      +17     
+ Partials       2008     2005       -3     

Files with missing lines	Coverage Δ
...erver/storage/file/session/FileSessionManager.java	56.60% <100.00%> (ø)
...org/apache/seata/server/session/SessionHolder.java	53.84% <11.11%> (-0.11%)	⬇️
...erver/storage/raft/session/RaftSessionManager.java	8.47% <28.57%> (+2.81%)	⬆️

... and 5 files with indirect coverage changes

[slievrly]

LGTM