[QC] Remove unused `clean` method from the query prototype (#38508)

* Remove unused `canRemove` method from `Aggregation` prototype

* Remove unused `clean` method from the `StructuredQuery` prototype

* Remove unused `cleanNesting` method from the `StructuredQuery` prototype

* Remove unused `_cleanEmpty` method from the `StructuredQuery` prototype

* Remove unused private methods from the `StructuredQuery` prototype

- cleanJoins
- cleanExpressions
- cleanFilters
- cleanFields

And the underlying
- _cleanClauseList

* Remove `clean` method from `NativeQuery` and `Query` prototypes