[BugFix] Fix deadlock in tablet schema map (backport #47539)

Why I'm doing:

There is deadlock in tablet schema map. In TabletSchemaMap::emplace, there is a local variable TabletSchemPtr ptr inside the lock scope. The TabletSchema object pointed by ptr may be destructed inside the lock scope, and its destructor will call TabletSchemaMap::erase which also try to lock, causing a deadlock.

What I'm doing:

Define the local variable TabletSchemPtr ptr outside the lock scope, making the destruction outside the lock scope.

Fixes #issue

What type of PR is this:

[x] BugFix
[ ] Feature
[ ] Enhancement
[ ] Refactor
[ ] UT
[ ] Doc
[ ] Tool

Does this PR entail a change in behavior?

[ ] Yes, this PR will result in a change in behavior.
[x] No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

[ ] Interface/UI changes: syntax, type conversion, expression evaluation, display information
[ ] Parameter changes: default values, similar parameters but with different default values
[ ] Policy changes: use new policy to replace old one, functionality automatically enabled
[ ] Feature removed
[ ] Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

[x] I have added test cases for my bug fix or my new feature
[ ] This pr needs user documentation (for new or modified features or behaviors)
- [ ] I have added documentation for my new feature or new function
[x] This is a backport pr

Bugfix cherry-pick branch check:

[x] I have checked the version labels which the pr will be auto-backported to the target branch
- [x] 3.3
- [x] 3.2
- [ ] 3.1
- [ ] 3.0
- [ ] 2.5
  This is an automatic backport of pull request #47539 done by Mergify.
  Why I'm doing:
  
  There is deadlock in tablet schema map. In TabletSchemaMap::emplace, there is a local variable TabletSchemPtr ptr inside the lock scope. The TabletSchema object pointed by ptr may be destructed inside the lock scope, and its destructor will call TabletSchemaMap::erase which also try to lock, causing a deadlock.