fix(validation): fix handling validation of subscribed generics

[provinzkraut]

Fix a bug that would lead to a TypeError when subscribed generics were used in a route handler signature and subject to validation.

from typing import Generic, TypeVar
from litestar import get
from litestar.testing import create_test_client

T = TypeVar("T")

class Foo(Generic[T]):
    pass

async def provide_foo() -> Foo[str]:
    return Foo()

@get("/", dependencies={"foo": provide_foo})
async def something(foo: Foo[str]) -> None:
    return None

with create_test_client([something]) as client:
    client.get("/")

[cofin]

LGTM

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

Attention: Patch coverage is 70.00000% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 98.28%. Comparing base (b6a640a) to head (e062ad6).

Files	Patch %	Lines
litestar/_signature/model.py	66.66%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3519      +/-   ##
==========================================
- Coverage   98.30%   98.28%   -0.02%     
==========================================
  Files         328      328              
  Lines       14876    14883       +7     
  Branches     2365     2367       +2     
==========================================
+ Hits        14624    14628       +4     
- Misses        115      116       +1     
- Partials      137      139       +2     

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[github-actions]

Documentation preview will be available shortly at https://litestar-org.github.io/litestar-docs-preview/3519