ECS: fix `opentelekomcloud_compute_instance_v2` flavor set for SWISS

[artem-lifshits]

Summary of the Pull Request

Fix flavor set for swisscloud

PR Checklist

• [x] Refers to: #2663
• [x] Schema updated.
• [x] Release notes added.

[otc-zuul[bot]]

Build succeeded. https://zuul.otc-service.com/t/eco/buildset/cdd76dea23cd46da97b985acd1d0e877

:heavy_check_mark: build-otc-releasenotes SUCCESS in 4m 23s :heavy_check_mark: noop SUCCESS in 0s :heavy_check_mark: otc-golangci-lint SUCCESS in 3m 25s :heavy_check_mark: golang-make-test SUCCESS in 3m 42s :heavy_check_mark: golang-make-vet SUCCESS in 2m 49s :heavy_check_mark: tflint SUCCESS in 1m 59s :heavy_check_mark: goreleaser-build SUCCESS in 7m 33s