Add missing NgIf and NgFor imports to AuthorizedItemSelectorComponent (8x)

[toniprieto]

References

• Related to [Port dspace-8_x] Update DSO creation and edition selectors in admin menu to use more specific authorization endpoints #5118

Description

During the backport of version x8 of #4918, two imports (NgIf and NgFor) were missing.
These were not needed in version 7x because it doesn’t use standalone components, and not required in main and dspace-9_x due to the use of the new Angular control flow syntax.
This PR simply adds the missing imports.

Instructions for Reviewers

To verify, open the item edit selector and check that it correctly lists the items available for editing.

Checklist

• My PR is created against the main branch of code (unless it is a backport or is fixing an issue specific to an older branch).
• My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• My PR passes ESLint validation using npm run lint
• My PR doesn't introduce circular dependencies (verified via npm run check-circ-deps)
• My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
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• If my PR fixes an issue ticket, I've linked them together.

[tdonohue]

👍 Thank you @toniprieto for catching this mistake. Looks good to me.