Default names shown in the field customization UI is wrong

### Version Information

Server Version: 2.16.0 (and previous versions)

### Environment

Any

### What is the current behaviour?

Default names shown in the field customization UI is wrong in different cases.

#### Case 1 (when naming conventions are **not** enabled)

Generated field names are:

But default values shown in the UI are:

The default values are wrong for update_users_by_pk, delete_users_by_pk and update_users_many.

#### Case 2 (when naming conventions are enabled and set to graphql-default)

Generated fields are in camel case but the default values shown are in snake case:

### What is the expected behaviour?

#### For Case 1

#### For Case 2

### Keywords

field customization, custom graphql root fields

Start by locating the field customization UI and the code that generates its default field names. Compare the displayed defaults with generated names for naming conventions disabled and graphql-default cases, including update_users_by_pk, delete_users_by_pk, and update_users_many. Done means the UI defaults match the generated fields in both cases and the behavior is covered by the relevant tests, if present.

Written by the indexing model from the issue text.