Remove censorship (naming model like "Model", if name != "Model" fix)

[gh0st-work]

Description

Moved ModelMeta field_map collecting block from under the condition if name != "Model":

Motivation and Context

Removes censorship. Whole app crashes if I name my model or meta-model like literally "Model".
Ex:

from tortoise import models


class Model(models.Model):
    ...

If you wanna know my opinion, better not to use __new__ and as litte as possible magic methods, you can use inspect.getmembers_static (link, python 3.11 only) in case of not calling __get__ and others.

How Has This Been Tested?

Tested in just CTRL+S and run, and reverse. Fixes the issue.

After successful fixing my issue, ran pytest.
Errors (i think, non mine):

platform win32 -- Python 3.11.0, pytest-7.2.0, pluggy-1.0.0

...

============================================================================================ short test summary info ============================================================================================= 
FAILED tests/test_queryset.py::TestQueryset::test_delete - tortoise.exceptions.OperationalError: near "ORDER": syntax error
FAILED tests/test_update.py::TestUpdate::test_bulk_update_json_value - tortoise.exceptions.OperationalError: unrecognized token: "{"
====================================================================== 2 failed, 1059 passed, 71 skipped, 4 xfailed, 117 warnings in 47.67s ======================================================================

Checklist:

• My code follows the code style of this project.
• I have read the CONTRIBUTING document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added the changelog accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[long2ice]

Thanks!