Assume v3 store is always not nil

[serathius]

V3 version of #19695

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: serathius

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [serathius]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[codecov]

Codecov Report

Attention: Patch coverage is 90.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 68.85%. Comparing base (839985d) to head (399f192).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
server/etcdserver/api/membership/cluster.go	90.00%	1 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
server/etcdserver/api/membership/storev2.go	50.53% <ø> (+5.34%)	⬆️
server/etcdserver/api/membership/cluster.go	89.02% <90.00%> (+0.43%)	⬆️

... and 23 files with indirect coverage changes

@@            Coverage Diff             @@
##             main   #19698      +/-   ##
==========================================
+ Coverage   68.76%   68.85%   +0.08%     
==========================================
  Files         421      421              
  Lines       35852    35836      -16     
==========================================
+ Hits        24655    24675      +20     
+ Misses       9773     9737      -36     
  Partials     1424     1424              

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 839985d...399f192. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[ahrtr]

similar comment as #19695 (comment)