fix: fix sqlserverflexalpha (#61)

## Description

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relates to #1234

## Checklist

- [ ] Issue was linked above
- [ ] Code format was applied: `make fmt`
- [ ] Examples were added / adjusted (see `examples/` directory)
- [x] Docs are up-to-date: `make generate-docs` (will be checked by CI)
- [ ] Unit tests got implemented or updated
- [ ] Acceptance tests got implemented or updated (see e.g. [here](f5f99d1709/stackit/internal/services/dns/dns_acc_test.go))
- [x] Unit tests are passing: `make test` (will be checked by CI)
- [x] No linter issues: `make lint` (will be checked by CI)

Reviewed-on: #61
Co-authored-by: Marcel S. Henselin <marcel.henselin@stackit.cloud>
Co-committed-by: Marcel S. Henselin <marcel.henselin@stackit.cloud>

go.mod

@@ -18,7 +18,6 @@ require (
 	github.com/spf13/cobra v1.10.2
 	github.com/stackitcloud/stackit-sdk-go/core v0.21.0
 	github.com/stackitcloud/stackit-sdk-go/services/iaasalpha v0.1.23-alpha
-	github.com/stackitcloud/stackit-sdk-go/services/sqlserverflex v1.4.1
 	github.com/teambition/rrule-go v1.8.2
 	gopkg.in/yaml.v3 v3.0.1
 )