[Release 1.29] Bump flannel version to v0.25.2

[thomasferrandiz]

Backport: #10146
Issue: #10217

[codecov]

Codecov Report

Attention: Patch coverage is 48.71795% with 20 lines in your changes are missing coverage. Please review.

Project coverage is 43.67%. Comparing base (86ad488) to head (7ebc690).

Files	Patch %	Lines
pkg/agent/flannel/flannel.go	48.71%	10 Missing and 10 partials ⚠️

Additional details and impacted files

@@               Coverage Diff                @@
##           release-1.29   #10220      +/-   ##
================================================
- Coverage         50.21%   43.67%   -6.54%     
================================================
  Files               158      158              
  Lines             14038    14048      +10     
================================================
- Hits               7049     6136     -913     
- Misses             5663     6742    +1079     
+ Partials           1326     1170     -156     

Flag	Coverage Δ
e2etests	36.60% <48.71%> (-10.11%)	⬇️
inttests	37.12% <48.71%> (-0.06%)	⬇️
unittests	16.55% <0.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.