[Fix] OBS: Fix OBS encryption disable

[artem-lifshits]

Summary of the Pull Request

Fix disable for obs bucket resource.

PR Checklist

• Refers to: OBS disable server side encryption not working #2768
• Tests added/passed.
• Documentation updated.
• Schema updated.
• Release notes added.

Acceptance Steps Performed

=== RUN   TestAccObsBucket_basic
=== PAUSE TestAccObsBucket_basic
=== CONT  TestAccObsBucket_basic
--- PASS: TestAccObsBucket_basic (84.85s)
PASS

Process finished with the exit code 0

[otc-zuul]

Build succeeded.
https://zuul.otc-service.com/t/eco/buildset/0aaacfd0aa474e419169b8e4bdec8ad8

✔️ build-otc-releasenotes SUCCESS in 4m 01s
✔️ noop SUCCESS in 0s
✔️ otc-golangci-lint SUCCESS in 3m 13s
✔️ golang-make-test SUCCESS in 3m 36s
✔️ golang-make-vet SUCCESS in 3m 04s
✔️ tflint SUCCESS in 1m 49s
✔️ goreleaser-build SUCCESS in 10m 32s