tagging escape bug

During testing of 5.0.6 rebase to develop https://github.com/openmicroscopy/openmicroscopy/pull/3187
Petr found that launching the Tagging dialog and loading tags fails if the P/D/I already has tags on it.

This is due to javascript escaping in commit:  687fe16a and is fixed by this PR.

To test, pick a tagged P/D/I and try to add additional tags. Make sure that the tagging dialog loads tags as expected.