Resourceadm: improve service selection in import link service modal

[mgunnerud]

Description

• Show link services sorted by service name (case-insensitive)
• Show link service in ComboBox as <serviceName> (<serviceCode>/<serviceEditionCode>)
• Add custom filter function to ComboBox to allow searching anywhere in option label
• Link service list should only show Altinn 2 link services (not Altinn 3 resources)
• Show empty option if no service is found when filtering list

Related Issue(s)

• 12985

Verification

• [ ] Your code builds clean without any errors or warnings
• [ ] Manual testing done (required)
• [ ] Relevant automated test added (if you find this hard, leave it and we'll help out)

Documentation

• [ ] User documentation is updated with a separate linked PR in altinn-studio-docs. (if applicable)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 91.47%. Comparing base (030107f) to head (b546a84). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #12990 +/- ## ========================================== - Coverage 91.47% 91.47% -0.01% ========================================== Files 1401 1401 Lines 19839 19838 -1 Branches 2397 2396 -1 ========================================== - Hits 18148 18147 -1 Misses 1427 1427 Partials 264 264 ```

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