fix: Removed omitempty from tags in ServerlessUpdateRequestParams

[cveticm]

This will allow for operators to remove all tags from Serverless Instances as tags will not be omitted when sending an empty array of tags.

Description

Please include a summary of the fix/feature/change, including any relevant motivation and context.

Link to any related issue(s):

Type of change:

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [x] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Required Checklist:

• [x] I have signed the MongoDB CLA
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have added any necessary documentation (if appropriate)
• [ ] I have run make fmt and formatted my code

Further comments

This is a minor change to allow AKO to remove all tags from a Serverless Instance

[matt-condon]

I think omitempty is very confusing in golang in relation to arrays (pointer values in general) Since we have array of pointers omitEmpty acts only on array itself - not on pointers: https://go.dev/play/p/N64Ggd7Gdth

@wtrocki This approach is a convention across this client, so I think we're fine to go with this for consistency (also any other approach would likely introduce a breaking change)

[wtrocki]

@wtrocki This approach is a convention across this client

I understand that. Trick is that removing ommitempty has no impact unless (breaking) suggestion by @gssbzn is applied.

https://go.dev/play/p/RKmHl4b0X6p