drop stackdriver exporter support

[dprotaso]

Part of knative/pkg#2183 & knative/pkg#2173

[codecov]

Codecov Report

Merging #11659 (640c559) into main (9c2ec0f) will increase coverage by 0.03%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main   #11659      +/-   ##
==========================================
+ Coverage   87.86%   87.90%   +0.03%     
==========================================
  Files         190      190              
  Lines        9253     9249       -4     
==========================================
  Hits         8130     8130              
+ Misses        874      872       -2     
+ Partials      249      247       -2     

Impacted Files	Coverage Δ
cmd/queue/main.go	0.51% <0.00%> (+<0.01%)	⬆️
pkg/reconciler/revision/resources/queue.go	100.00% <ø> (ø)
pkg/reconciler/configuration/configuration.go	88.46% <0.00%> (+2.30%)	⬆️

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[dprotaso]

/assign @evankanderson @skonto

[evankanderson]

/lgtm
/approve

[knative-prow-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dprotaso, evankanderson

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Needs approval from an approver in each of these files:

• cmd/queue/OWNERS [dprotaso,evankanderson]
• config/OWNERS [dprotaso,evankanderson]
• pkg/metrics/OWNERS [dprotaso,evankanderson]
• pkg/reconciler/OWNERS [dprotaso,evankanderson]

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