Sequence[Mapping[str, Any]] won't allow dict with different layouts

Bug Report

When a function takes Sequence[Mapping[str, Any]] and a call is made with dictionaries having different fields, a cryptic error is reported that seems to indicate strange affinity for same type even for different field types.

This use is typical for passing in a Mongo DB pipeline list, which is flagged as an error, while there is none, like in this method:

https://pymongo.readthedocs.io/en/stable/api/pymongo/collection.html#pymongo.collection.Collection.aggregate

To Reproduce

mypy --strict --check-untyped-defs --strict-equality \
    --warn-redundant-casts --warn-incomplete-stub \
    --warn-unreachable --install-types \
    --non-interactive app.py

def fn(p: Sequence[Mapping[str, Any]]) -> None:
    pass
p = [{"x": 1}, {"y": "A"}]
fn(p)                               # <-- error reported
fn([{"x": 1}, {"y": "A"}])          # <-- no error
q = [{"x": "1"}, {"y": "A", "z": "3"}]
fn(q)                               # <-- no error (but will be if any number is unquoted)

The error is reported for p:

app.py:6: error: Argument 1 to "fn" has incompatible type "List[object]"; expected "Sequence[Mapping[str, Any]]" [arg-type]

Expected Behavior

Sequence[Any] may be used to pass in different types and should allow dictionaries with arbitrarily different layouts for Sequence[Mapping[str, Any]].

Actual Behavior

mypy enforces some internal logic that cannot be described as enforcing same layout, which is indicated by q having very different dictionaries and not triggering this error. However, if any of the numbers in q is unquoted, the error is reported for the last fn call.

Your Environment

• Mypy version used: mypy 1.2.0 (compiled: yes)
• Mypy command-line flags: see above
• Mypy configuration options from mypy.ini (and other config files): None (not used)
• Python version used: Python 3.10.10

Reproduce the report by putting the examples in app.py and running the documented mypy command with Python 3.10. Compare the inferred types for the assigned list and the inline list, then trace the relevant type-checking behavior. Done means dictionaries with different layouts are accepted when passed as Sequence[Mapping[str, Any]] without weakening unrelated type checks.