Re-enable 'class-methods-use-this' eslint rule 

## Action item
The eslint rule [class-methods-use-this](https://eslint.org/docs/latest/rules/class-methods-use-this) needs to enabled, and files that do not follow the rule need to be fixed.

Related discussion: https://github.com/centerofci/mathesar/pull/1876#discussion_r1026673906
