Trigger create and expose OIDC service account

[creydr]

Fixes #7222

Proposed Changes

• 🎁 Expose the name of the OIDC service account in the Triggers .status.auth.serviceAccountName
• 🎁 Create the OIDC service account of the Trigger

Release Note

Expose the Triggers OIDC service account name in the Triggers .status.auth.serviceAccountName

[creydr]

/hold
until #7173 is fixed and we can rebase (d678c3d can be removed then)

[codecov]

Codecov Report

Attention: 26 lines in your changes are missing coverage. Please review.

Comparison is base (ff9444d) 77.66% compared to head (8941b64) 77.54%.
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7299      +/-   ##
==========================================
- Coverage   77.66%   77.54%   -0.13%     
==========================================
  Files         250      250              
  Lines       13436    13491      +55     
==========================================
+ Hits        10435    10461      +26     
- Misses       2478     2506      +28     
- Partials      523      524       +1     

Files	Coverage Δ
pkg/apis/duck/v1/subscribable_types.go	100.00% <ø> (ø)
pkg/apis/eventing/v1/trigger_types.go	100.00% <ø> (ø)
pkg/apis/flows/v1/parallel_types.go	100.00% <ø> (ø)
pkg/apis/flows/v1/sequence_types.go	100.00% <ø> (ø)
pkg/apis/messaging/v1/subscription_types.go	66.66% <ø> (ø)
pkg/reconciler/broker/trigger/controller.go	93.90% <100.00%> (+0.75%)	⬆️
pkg/reconciler/broker/trigger/trigger.go	83.78% <100.00%> (+1.06%)	⬆️
pkg/apis/eventing/v1/trigger_lifecycle.go	51.00% <50.00%> (-0.09%)	⬇️
pkg/auth/serviceaccount.go	52.17% <4.34%> (-47.83%)	⬇️

... and 2 files with indirect coverage changes

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[creydr]

rebased as #7173 is done
/unhold

@pierDipi could you check on this?

[creydr]

@pierDipi since we have a new status condition, we need to update the other broker implementations too (at least the tests). We will probably need to do that for the other resources (e.g. Subscriptions) too :/

[creydr]

/retest

[pierDipi]

/lgtm
/approve

[knative-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: creydr, pierDipi

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