[Release 1.30] Add guardrail for etcd-snapshot

[manuelbuil]

Backport: #11314
Issue: #11390

FOR JANUARY RELEASE

[codecov]

Codecov Report

Attention: Patch coverage is 72.72727% with 3 lines in your changes missing coverage. Please review.

Project coverage is 42.23%. Comparing base (c79db1b) to head (4dd0f5f).

Files with missing lines	Patch %	Lines
pkg/cluster/managed.go	72.72%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@               Coverage Diff                @@
##           release-1.30   #11394      +/-   ##
================================================
- Coverage         46.75%   42.23%   -4.52%     
================================================
  Files               179      179              
  Lines             18729    18739      +10     
================================================
- Hits               8757     7915     -842     
- Misses             8625     9625    +1000     
+ Partials           1347     1199     -148     

Flag	Coverage Δ
e2etests	34.27% <72.72%> (-7.91%)	⬇️
inttests	34.67% <72.72%> (-0.07%)	⬇️
unittests	13.72% <0.00%> (-0.01%)	⬇️

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