PD may be panic when enabling `tidb_enable_tso_follower_proxy` and restart PD

## Bug Report



### What did you do?



1. enable `tidb_enable_tso_follower_proxy`
2. many tidb instances(40+) and the write traffic is very high.
3. restart PD, if it is the PD leader, the trigger probability will also increase.

### What did you expect to see?

PD restart successfully

### What did you see instead?

PD panic

[pd_log.log](https://github.com/user-attachments/files/18250154/pd_log.log)


### What version of PD are you using (`pd-server -V`)?

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PD may be panic when enabling `tidb_enable_tso_follower_proxy` and restart PD #8950

Bug Report

What did you do?

What did you expect to see?

What did you see instead?

What version of PD are you using (`pd-server -V`)?

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PD may be panic when enabling tidb_enable_tso_follower_proxy and restart PD #8950

Description

Bug Report

What did you do?

What did you expect to see?

What did you see instead?

What version of PD are you using (pd-server -V)?

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

PD may be panic when enabling `tidb_enable_tso_follower_proxy` and restart PD #8950

What version of PD are you using (`pd-server -V`)?