* update customer service prep
* expand on the update customer groups test case
* add the test case for customer group update
* docs for `groups` prop on update customer endpoint
* refactor, update comments
* expend on integration tests, add customer mock with a group
* refactor to use `customerGroupService.list` method
* update units
* remove `updateCustomerGroups`
* fix rebase conflict
* fix customer seed data, add JoinTable on groups
* group retrieval using the expand param
* fix: use `buildQuery_`
* fix: validation for `groups`, enable `expand`param on update customer endpoint
* fix: remove fileds form the `FilterableCustomerGroupProps`
* fix: spearate body/query validation
Co-authored-by: fPolic <frane@medusajs.com>