fix panic without PV permission

[csuzhangxc]

What problem does this PR solve?

fix #4797

NOTE, in this case, some volume statuses will not be updated

      volumes:
        tikv:
          boundCount: 1
          currentCapacity: 1Gi
          currentCount: 1
          currentStorageClass: standard
          modifiedCapacity: 1Gi
          modifiedCount: 0
          modifiedStorageClass: test
          name: tikv
          resizedCapacity: 1Gi
          resizedCount: 0

What is changed and how does it work?

Code changes

• Has Go code change
• Has CI related scripts change

Tests

• Unit test
• E2E test
• Manual test
• No code

Side effects

• Breaking backward compatibility
• Other side effects:

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release Notes

Please refer to Release Notes Language Style Guide before writing the release note.

Fix the issue that TiDB Operator panics if without PV permission

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• KanShiori
• liubog2008

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[codecov-commenter]

Codecov Report

Merging #4837 (7b0c25b) into master (703375a) will increase coverage by 8.53%.
The diff coverage is 0.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4837      +/-   ##
==========================================
+ Coverage   59.99%   68.52%   +8.53%     
==========================================
  Files         224      228       +4     
  Lines       25356    28428    +3072     
==========================================
+ Hits        15212    19481    +4269     
+ Misses       8704     7491    -1213     
- Partials     1440     1456      +16     

Flag	Coverage Δ
e2e	52.91% <0.00%> (?)
unittest	59.97% <0.00%> (-0.02%)	⬇️

[KanShiori]

Add a comment in the VolumeModifier interface to note the pv may be nil and the reason.

[csuzhangxc]

/test pull-e2e-kind
/test pull-e2e-kind-serial

[csuzhangxc]

/test pull-e2e-kind-serial

[csuzhangxc]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 7b0c25b

[csuzhangxc]

/test pull-e2e-kind-serial

[csuzhangxc]

/test pull-e2e-kind-serial

[csuzhangxc]

/test pull-e2e-kind-serial

[csuzhangxc]

/test pull-e2e-kind-serial

[csuzhangxc]

/cherry-pick release-1.4

[ti-chi-bot]

@csuzhangxc: new pull request created to branch release-1.4: #4840.

In response to this:

/cherry-pick release-1.4

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