feat(UserMigration): Overwork migration to include all settings (trusted senders)

[DerDreschner]

This PR belongs to a series of PRs that will enhance the user migration to include all settings.

Included changes in this PR:

• Remove all trusted senders for the user before import
• Allow export of trusted senders
• Allow import of trusted senders
• Unit tests for import and export

I didn't include any unit tests for the removal code as that only calls another function.

Please ignore the failed CI run regarding the unconventional commit message. That happens as I tag another feature branch for better overview here.

Refs #12001

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Extends the mail user-migration flow to include “trusted senders” settings by exporting/importing them and clearing existing entries before import.

Changes:

• Add TrustedSendersMigrationService to export/import/remove trusted senders during migration.
• Wire the service into MailAccountMigrator export/import/delete flows.
• Add PHPUnit unit tests covering trusted senders export/import scenarios and invalid inputs.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 9 comments.

File	Description
lib/UserMigration/Service/TrustedSendersMigrationService.php	Implements export/import/removal of trusted senders and validates import structure.
lib/UserMigration/MailAccountMigrator.php	Integrates trusted senders migration into the overall mail migrator lifecycle.
tests/Unit/UserMigration/Service/TrustedSendersMigrationServiceTest.php	Adds unit tests for trusted senders export/import behavior and error cases.

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[Copilot]

The new validation logic has multiple branches that aren’t covered by the current unit tests (e.g., an entry that is not an array, missing email/type, or non-string values). Add unit tests that assert UserMigrationException is thrown for these specific malformed structures (and that non-array items don’t cause a TypeError once fixed).

Suggested change

	$trustedSenderArrayIsValid = is_array($trustedSender);
	$emailIsValid = array_key_exists('email', $trustedSender) && is_string($trustedSender['email']);
	$typeIsValid = array_key_exists('type', $trustedSender) && is_string($trustedSender['type']);
	if (!$trustedSenderArrayIsValid || !$emailIsValid || !$typeIsValid) {
	if (!is_array($trustedSender)) {
	throw new UserMigrationException('Invalid trusted sender entry');
	}
	$emailIsValid = array_key_exists('email', $trustedSender) && is_string($trustedSender['email']);
	$typeIsValid = array_key_exists('type', $trustedSender) && is_string($trustedSender['type']);
	if (!$emailIsValid || !$typeIsValid) {

[kesselb]

If throwing an exception in this method aborts the import, I would suggest to ignore the exception, catch it, or just go ahead. While losing all trusted senders might be annoying, not being able to complete the import might be even more annoying.