Fix bug in pydantic_model_creator when include does not contain foreing keys.

[Abdeldjalil-H]

When the function pydantic_model_creator is used to create a model and the parameter include is passed #1430, this will raise an error if the relation is passed but not the foreign key value. Here is an example:

class Tournament(Model):
    """
    This references a Tournament
    """

    id = fields.IntField(primary_key=True)
    name = fields.CharField(max_length=100)


class Event(Model):
    """
    This references an Event in a Tournament
    """

    id = fields.IntField(primary_key=True)
    name = fields.CharField(max_length=100)

    tournament: fields.ForeignKeyRelation[Tournament] = fields.ForeignKeyField(
        "models.Tournament", related_name="events", description="The Tournament this happens in"
    )

# Initialise model structure early.
Tortoise.init_models(["__main__"], "models")

Event_Pydantic = pydantic_model_creator(Event, include=["tournament"])

The above code will raise a KeyError exception because tournament is not included, thus it will not be found in field_map variable of the function field_map_update. To fix this we can replace the del with pop method.

Checklist:

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

[coveralls]

Pull Request Test Coverage Report for Build 10132332526

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 89.158%

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Totals
Change from base Build 10115140001:	0.0%
Covered Lines:	5939
Relevant Lines:	6550

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