fix: column id can be ambiguous in group filter with extensions

[iPurpl3x]

Changes proposed in this pull request:
Changed 'id' to 'groups.id' to avoid Column 'id' in where clause is ambiguous error.

This error normally doesn't occur, but if an extension adds an id column to the group_user table, then this error would occur.

(Adding that column helps when one wants to chunkById() on the group_user model)

Reviewers should focus on:
Nothing is broken by this minor change.

Necessity

• Has the problem that is being solved here been clearly explained?
• If applicable, have various options for solving this problem been considered?
• For core PRs, does this need to be in core, or could it be in an extension?
• Are we willing to maintain this for years / potentially forever?

Confirmed

• Backend changes: tests are green (run composer test).
• Core developer confirmed locally this works as intended.
• Tests have been added, or are not appropriate here.

[SychO9]

You made a typo, it's groups.id

[iPurpl3x]

Good catch @SychO9! I fixed it.

[SychO9]

In the long term, we should look into prefixing all columns with table names in filters/gambits to avoid these issues.