sequence or mapping pattern on generic variables makes case unreachable

**Describe the bug**

Applying sequence or mapping pattern on a generic variable makes that case unreachable, and false positive `reportUnnecessaryComparison` is reported (if enabled).

**Code or Screenshots**

[pyright-play.net](https://pyright-play.net/?code=MQAgDgngTglg5gCwC4C4RQKZgPZSQVQDtCMBjDAZwoEMoIBhbAWzFpgu0IF4koBXDAChBAEwwAzEOIDaAFQC6ACgAeaWQEoUgkDpBNqSUghCrtu86WoUMIAPoAaO1vMvdYWISSKARNYCO3uo6oCLsYAA21BAYIiBWIHyEmNRG1ABG4UKuOpbWIADe3gDW3mi2AL7O2ebuMJ4%2B%2BmCBwSChFBFRMXEUCUkYKQjpmWauuTa2VdU6rFTC4oqKAIz2AEzq6oLzhSVo3gBu3uXqQA)

```python
# pyright: reportUnnecessaryComparison=true

def f[T](x: T):
match x:
case _, _:
print("seq") # displayed as unreachable
case {"k": _}:
print("map") # displayed as unreachable
case _:
pass

f((1,2))
f({"k": "v"})
```

```
$ pyright ma.py
ma.py
ma.py:3:13 - warning: TypeVar "T" appears only once in generic function signature
Use "object" instead (reportInvalidTypeVarUse)
ma.py:5:14 - error: Pattern will never be matched for subject type "T@f" (reportUnnecessaryComparison)
ma.py:7:14 - error: Pattern will never be matched for subject type "T@f" (reportUnnecessaryComparison)
2 errors, 1 warning, 0 informations
```

```
$ python ma.py
seq
map
```

**VS Code extension or command-line**

command-line tool, 1.1.403

Reproduce the diagnostic with the linked pyright-play example or ma.py using reportUnnecessaryComparison=true, then run the command-line tool on the sample. Trace how the two match patterns are classified for generic T; done means tuple and mapping cases are not reported as unreachable while the sample calls continue to work.

Written by the indexing model from the issue text.