ci: fix check for changes to work with deleted files (#850)

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

## Description

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

Seems like any_changed doesn't take into account deleted files. Changing
to any_modified
https://github.com/tj-actions/changed-files/tree/v44/?tab=readme-ov-file#output_any_modified

## Related Issue(s)

- #{issue number}

## 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)

.github/workflows/action-check-for-changes.yml

@@ -23,11 +23,11 @@ jobs:
     name: Filter
     runs-on: ubuntu-latest
     outputs:
-      hasBackendChanges: ${{ steps.filter.outputs.backend_any_changed == 'true' }}
-      hasAzureChanges: ${{ steps.filter.outputs.azure_any_changed == 'true' }}
-      hasSlackNotifierChanges: ${{ steps.filter.outputs.slackNotifier_any_changed == 'true'}}
-      hasSchemaChanges: ${{ steps.filter.outputs.schema_any_changed == 'true'}}
-      hasMigrationChanges: ${{ steps.filter.outputs.migration_any_changed == 'true'}}
+      hasBackendChanges: ${{ steps.filter.outputs.backend_any_modified == 'true' }}
+      hasAzureChanges: ${{ steps.filter.outputs.azure_any_modified == 'true' }}
+      hasSlackNotifierChanges: ${{ steps.filter.outputs.slackNotifier_any_modified == 'true'}}
+      hasSchemaChanges: ${{ steps.filter.outputs.schema_any_modified == 'true'}}
+      hasMigrationChanges: ${{ steps.filter.outputs.migration_any_modified == 'true'}}
     steps:
       - name: Checkout
         uses: actions/checkout@v4