fix: workaround for github number error in dispatch workflow (#1367)

<!--- Provide a general summary of your changes in the Title above -->

Workaround for issue mentioned here:
https://github.com/orgs/community/discussions/67182
Made testSuitePath a type choice and added tests to the list

<!--- Describe your changes in detail -->

## Related Issue(s)

- #1326 

## 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

- [ ] Documentation is updated (either in `docs`-directory, Altinnpedia
or a separate linked PR in
[altinn-studio-docs.](https://github.com/Altinn/altinn-studio-docs), if
applicable)


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
- Enhanced input handling for performance tests, allowing users to
select from predefined test suite paths.
- Improved processing of virtual users (VUs) input for better validation
and structure.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: dagfinno

.github/workflows/dispatch-k6-performance.yml

@@ -29,8 +29,8 @@ on:
       vus:
         description: 'Number of VUS'
         required: true
-        type: number
         default: 10
+        type: number
       duration:
         description: 'Duration of test, ie 30s, 1m, 10m'
         required: true
@@ -40,6 +40,10 @@ on:
         description: 'Path to test suite to run'
         required: true
         default: 'tests/k6/tests/serviceowner/performance/create-dialog.js'
+        type: choice
+        options:
+          - 'tests/k6/tests/serviceowner/performance/create-dialog.js'
+          - 'tests/k6/tests/enduser/performance/simple-search.js'
 
 jobs:
   k6-performance:
@@ -54,7 +58,7 @@ jobs:
       environment: ${{ inputs.environment }}
       apiVersion: ${{ inputs.apiVersion }}
       testSuitePath: ${{ inputs.testSuitePath }}
-      vus: ${{ inputs.vus }}
+      vus: ${{ fromJson(inputs.vus) }}
       duration: ${{ inputs.duration }}
       tokens: ${{ inputs.tokens }}