fix: add object_expression/object_member support to reformatter (#5776)
# fix: add object_expression/object_member support to reformatter
## Summary
The reformatter was missing handlers for `object_expression` and
`object_member` rules, causing it to always fail when encountering
object literals (e.g. partial index `where` clauses).
## Changes
* `psl/schema-ast/src/reformat.rs` : Add `reformat_object_expression`
and `reformat_object_member` functions
* `psl/psl/tests/reformatter/` : Add corresponding test fixtures for
object_expression and object_member.
fix: prisma/prisma#29180