fix #5546: remove incorrect for attribute from label in array form fi…

[guillermo-escire]

References

Fixes #5546

Description

Removes the incorrect for attribute from labels associated with array-type form fields in the submission form, replacing it with aria-labelledby on the array container to maintain accessibility without triggering browser warnings.

Instructions for Reviewers

List of changes in this PR:

• In ds-dynamic-form-control-container.component.html, changed the label's [for] binding to use [attr.for] with a conditional that sets it to null when the model type is ARRAY, preventing the browser accessibility warning.
• In dynamic-form-array.component.html, added [attr.aria-labelledby] to the array container div, pointing to the label's id, maintaining proper accessibility.
• Added a test in ds-dynamic-form-control-container.component.spec.ts to verify the label has no for attribute when the model type is ARRAY.
• Added a test in dynamic-form-array.component.spec.ts to verify the array container has the correct aria-labelledby attribute.

How to test:

1. Open the submission form at /workspaceitems/{id}/edit
2. Open DevTools (F12) and go to the Console tab
3. Filter by Incorrect use — the warning should no longer appear
4. Inspect the "Other Titles" field — the should have no for attribute and the array
   should have aria-labelledby pointing to the label's id

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