fix(frontend): disable repeat remove buttons

[anthonychengit]

What changes were proposed in this PR?

Rename the repeat row's *ngFor variable so it no longer shadows the component's field. The remove buttons now read the section-level templateOptions.disabled, matching the add button.

Before	After
Remove buttons stay active while the section is disabled.	All remove buttons and the add button are disabled together.

Permanent rendering tests cover both directions: every remove button is disabled for a disabled section, and every remove button remains available otherwise.

Any related issues, documentation, discussions?

Closes #7431

How was this PR tested?

cd frontend
node node_modules\@angular\cli\bin\ng.js test --watch=false --include src/app/common/formly/repeat-dnd/repeat-dnd.component.spec.ts
node .yarn\releases\yarn-4.14.1.cjs run format:ci
git diff --check

Result: 14 tests passed; the frontend Prettier and ESLint CI check passed; git diff --check passed.

The before/after evidence was captured from the actual Angular component in Playwright Chromium with templateOptions.disabled = true.

Was this PR authored or co-authored using generative AI tooling?

Generated-by: OpenAI Codex (GPT-5)

[github-actions]

Automated Reviewer Suggestions

Based on the git blame history of the changed files, we recommend the following reviewers:

• Contributors with relevant context: @yrenat, @aglinxinyuan
  You can notify them by mentioning @yrenat, @aglinxinyuan in a comment.

[github-actions]

Backport auto-label report

This fix: PR was checked against each actively-supported release branch. release/* labels drive the post-merge backport, so add or remove one to change where this fix lands.

Release branch	Analysis
✅ release/v1.2	Change detected on this branch — label added; this fix is queued to backport here. Requested review from @xuang7.

Auto-label run.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.21%. Comparing base (5de9bf9) to head (8341d1d).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #7995   +/-   ##
=========================================
  Coverage     93.21%   93.21%           
  Complexity     4664     4664           
=========================================
  Files          1175     1175           
  Lines         47646    47646           
  Branches       5319     5319           
=========================================
+ Hits          44413    44414    +1     
  Misses         1752     1752           
+ Partials       1481     1480    -1     

Flag	Coverage Δ		*Carryforward flag
access-control-service	81.00% <ø> (ø)		Carriedforward from 5de9bf9
agent-service	99.32% <ø> (ø)		Carriedforward from 5de9bf9
amber	89.31% <ø> (ø)		Carriedforward from 5de9bf9
computing-unit-managing-service	73.67% <ø> (ø)		Carriedforward from 5de9bf9
config-service	86.73% <ø> (ø)		Carriedforward from 5de9bf9
file-service	86.70% <ø> (ø)		Carriedforward from 5de9bf9
frontend	95.67% <100.00%> (+<0.01%)	⬆️
notebook-migration-service	79.31% <ø> (ø)		Carriedforward from 5de9bf9
pyamber	97.74% <ø> (ø)		Carriedforward from 5de9bf9
workflow-compiling-service	77.19% <ø> (ø)		Carriedforward from 5de9bf9

*This pull request uses carry forward flags. Click here to find out more.

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[aglinxinyuan]

Please add a before-and-after screenshot.