Add k8s 1.25 to the nightly matrix

[lucacome]

With the recent update in #3358 the latest is now 1.26.0. This PR adds the previous latest 1.25.3 to the matrix for nightly runs.

[codecov-commenter]

Codecov Report

Merging #3359 (8a55e17) into main (1396149) will decrease coverage by 0.99%.
The diff coverage is 17.62%.

@@            Coverage Diff             @@
##             main    #3359      +/-   ##
==========================================
- Coverage   52.56%   51.56%   -1.00%     
==========================================
  Files          59       60       +1     
  Lines       16080    16678     +598     
==========================================
+ Hits         8452     8600     +148     
- Misses       7351     7788     +437     
- Partials      277      290      +13     

Impacted Files	Coverage Δ
cmd/nginx-ingress/flags.go	29.85% <0.00%> (-4.57%)	⬇️
cmd/nginx-ingress/main.go	0.00% <0.00%> (ø)
cmd/nginx-ingress/utils.go	0.00% <0.00%> (ø)
internal/configs/configurator.go	35.16% <0.00%> (-1.90%)	⬇️
internal/configs/version1/config.go	0.00% <ø> (ø)
internal/k8s/handlers.go	6.49% <0.00%> (-0.34%)	⬇️
internal/k8s/spiffe.go	0.00% <ø> (ø)
internal/k8s/task_queue.go	0.00% <0.00%> (ø)
internal/k8s/utils.go	14.08% <0.00%> (-0.63%)	⬇️
internal/nginx/manager.go	0.00% <0.00%> (ø)
... and 18 more

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