Fix profile selection when linking a channel to an item

[jimtng]

Regression from #2690

Reported here:
https://community.openhab.org/t/enocean-impossible-to-link-a-rockerswitch-channel-with-an-item-in-main-ui-there-is-no-profile-available-for-the-selected-item/160987

When creating a Thing channel link to an item, the profile selection are disabled. This presents two problems:

• It made linking a trigger channel to an item not possible, because a profile must be selected, but they're disabled.
• Linking a non-trigger channel to a new item is possible, but selecting a profile is not possible at link creation. The user has to create the link without a profile first, then go back to edit the link in order to assign a profile.

This PR fixes both these problems.

Note this needs to be backported to 4.3.x

[relativeci]

#2580 Bundle Size — 10.9MiB (~+0.01%).

6047ecd(current) vs 0ead7b8 main#2579(baseline)

Warning

Bundle contains 2 duplicate packages – View duplicate packages

Bundle metrics   1 change

	Current #2580	Baseline #2579
Initial JS	1.92MiB	1.92MiB
Initial CSS	577.83KiB	577.83KiB
Cache Invalidation	18.31%	17.58%
Chunks	226	226
Assets	249	249
Modules	2947	2947
Duplicate Modules	152	152
Duplicate Code	1.8%	1.8%
Packages	96	96
Duplicate Packages	2	2

Bundle size by type   1 change 1 regression

	Current #2580	Baseline #2579
JS	9.11MiB (~+0.01%)	9.11MiB
CSS	866.74KiB	866.74KiB
Fonts	526.1KiB	526.1KiB
Media	295.6KiB	295.6KiB
IMG	140.74KiB	140.74KiB
HTML	1.38KiB	1.38KiB
Other	871B	871B

Bundle analysis report Branch jimtng:fix-add-link Project dashboard

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[jimtng]

@ssalonen would you mind testing this to see whether the changes in this PR stilll works for #1478 ?

The test JAR can be found here if you don't want to build it yourself:
https://github.com/jimtng/openhab-webui/releases/tag/ui-link-fix-4.3.1-1

[florian-h05]

@jimtng See #2941, this fixes the same issue and a bit more and refactors the code a bit.
I will therefore close your PR in favour of mine.

[ssalonen]

I am unable to test this due to lack of time, sorry