Session Affinity ChangeOnFailure should be boolean

[ElvinEfendi]

What this PR does / why we need it:

• Use GetBoolAnnotation helper instead of GetStringAnnotation and verifying manually using Regexp

• Fix variable naming

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@c6c6f51). Click here to learn what that means.
The diff coverage is 50%.

@@            Coverage Diff            @@
##             master    #4166   +/-   ##
=========================================
  Coverage          ?   57.63%           
=========================================
  Files             ?       87           
  Lines             ?     6463           
  Branches          ?        0           
=========================================
  Hits              ?     3725           
  Misses            ?     2307           
  Partials          ?      431

Impacted Files	Coverage Δ
internal/ingress/types.go	0% <ø> (ø)
...ternal/ingress/annotations/sessionaffinity/main.go	55.26% <50%> (ø)

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[aledbf]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf, ElvinEfendi

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