[chore] update error message (#4311)

Signed-off-by: nicole mikołajczyk <git@mkljczk.pl>

# Description

## Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: `[ ]` -> `[x]`

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [ ] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [ ] I/we have commented the added code, particularly in hard-to-understand areas.
- [ ] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [x] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4311
Co-authored-by: nicole mikołajczyk <git@mkljczk.pl>
Co-committed-by: nicole mikołajczyk <git@mkljczk.pl>

internal/processing/status/fave.go

@@ -65,7 +65,7 @@ func (p *Processor) getFaveableStatus(
 
 	fave, err := p.state.DB.GetStatusFave(ctx, requester.ID, target.ID)
 	if err != nil && !errors.Is(err, db.ErrNoEntries) {
-		err = fmt.Errorf("getFaveTarget: error checking existing fave: %w", err)
+		err = gtserror.Newf("error checking existing fave: %w", err)
 		return nil, nil, gtserror.NewErrorInternalError(err)
 	}