Adding TARGET_ARCH to tag definition when run on CI true

[fjglira]

Adding export TAG=pr-- when CI is true to avoid race conditions when building and pushing multiple arch jobs at the same time

What type of PR is this?

• Enhancement / New Feature
• Bug Fix
• Refactor
• Optimization
• Test
• Documentation Update

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

Related Issue/PR #

Additional information:

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.28%. Comparing base (0733256) to head (87cb9d8).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1583      +/-   ##
==========================================
+ Coverage   80.83%   81.28%   +0.44%     
==========================================
  Files          50       50              
  Lines        2458     2458              
==========================================
+ Hits         1987     1998      +11     
+ Misses        347      340       -7     
+ Partials      124      120       -4     

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[fjglira]

/test e2e-kind

[istio-testing]

In response to a cherrypick label: #1583 failed to apply on top of branch "release-1.26":

Applying: Adding TARGET_ARCH to tag definition when run on CI true
Using index info to reconstruct a base tree...
M	tests/e2e/common-operator-integ-suite.sh
Falling back to patching base and 3-way merge...
Auto-merging tests/e2e/common-operator-integ-suite.sh
CONFLICT (content): Merge conflict in tests/e2e/common-operator-integ-suite.sh
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Patch failed at 0001 Adding TARGET_ARCH to tag definition when run on CI true

[istio-testing]

In response to a cherrypick label: new issue created for failed cherrypick: #1584

[istio-testing]

In response to a cherrypick label: new pull request created: #1585

[istio-testing]

In response to a cherrypick label: new pull request created: #1586