Fix e2e externalName test

[aledbf]

What this PR does / why we need it:

httpbin.org is validating the host field now

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Which issue/s this PR fixes

How Has This Been Tested?

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have added tests to cover my changes.
• All new and existing tests passed.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf

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• OWNERS [aledbf]

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[codecov-commenter]

Codecov Report

Merging #5725 into master will increase coverage by 0.01%.
The diff coverage is 21.42%.

@@            Coverage Diff             @@
##           master    #5725      +/-   ##
==========================================
+ Coverage   58.65%   58.66%   +0.01%     
==========================================
  Files          88       88              
  Lines        6951     6956       +5     
==========================================
+ Hits         4077     4081       +4     
  Misses       2425     2425              
- Partials      449      450       +1     

Impacted Files	Coverage Δ
cmd/nginx/main.go	5.37% <0.00%> (ø)
internal/ingress/controller/store/store.go	58.57% <50.00%> (-0.20%)	⬇️
internal/ingress/metric/collectors/process.go	90.62% <0.00%> (+2.08%)	⬆️

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[aledbf]

/test pull-ingress-nginx-e2e-1-18
/test pull-ingress-nginx-e2e-1-16
/test pull-ingress-nginx-e2e-1-15