fix: Fix various panics

[dthomson25]

Fixes panics in:

• metrics provider
• Ingress controller
• Restarting Rollouts

[codecov-commenter]

Codecov Report

Merging #603 into master will decrease coverage by 0.08%.
The diff coverage is 55.55%.

@@            Coverage Diff             @@
##           master     #603      +/-   ##
==========================================
- Coverage   85.80%   85.71%   -0.09%     
==========================================
  Files          87       87              
  Lines        8297     8380      +83     
==========================================
+ Hits         7119     7183      +64     
- Misses        844      859      +15     
- Partials      334      338       +4     

Impacted Files	Coverage Δ
utils/kubeclientmetrics/metric.go	89.20% <20.00%> (-2.65%)	⬇️
controller/metrics/client.go	100.00% <100.00%> (ø)
ingress/ingress.go	59.49% <100.00%> (ø)
rollout/restart.go	95.78% <100.00%> (+0.04%)	⬆️
utils/analysis/helpers.go	90.27% <0.00%> (-4.85%)	⬇️
utils/analysis/filter.go	97.72% <0.00%> (-2.28%)	⬇️
rollout/pause.go	99.14% <0.00%> (+0.03%)	⬆️
rollout/canary.go	85.93% <0.00%> (+0.05%)	⬆️
rollout/sync.go	74.75% <0.00%> (+0.06%)	⬆️
rollout/context.go	98.56% <0.00%> (+0.09%)	⬆️
... and 2 more

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