[analyzer] Switch cases for destructured records do not promote types

When trying to have switch cases where the record fields each match a certain subtype of a common supertype, it appears that when switching on the destructured variables, the type promotion does not happen. However, as indicated in `demoB`, it could work without destructuring. Is this the intended behavior?

Example:

```dart
class Foo {}

class FooA extends Foo {}

class FooB extends Foo {}

void funA(FooA first, FooA second) {}
void funB(FooB first, FooB second) {}

void demoA(Foo first, Foo second) {
switch ((first, second)) {
case ((FooA(), FooA())):
// The argument type 'Foo' can't be assigned to the parameter type 'FooA'
funA(first, second);
case ((FooB(), FooB())):
// The argument type 'Foo' can't be assigned to the parameter type 'FooB'
funB(first, second);
}
}

void demoB(Foo first, Foo second) {
final record = (first, second);
switch (record) {
case ((FooA(), FooA())):
funA(record.$1, record.$2); // OK
case ((FooB(), FooB())):
funB(record.$1, record.$2); // OK
}
}
```

Dart info:

```
- Dart 3.5.0-319.0.dev (dev) (Sun Jun 30 17:06:39 2024 -0700) on "linux_x64"
- on linux / Linux 6.1.0-22-amd64 dart-lang/sdk#1 SMP PREEMPT_DYNAMIC Debian 6.1.94-1 (2024-06-21)
```

Related:

- dart-lang/sdk#45357
- https://github.com/zulip/zulip-flutter/pull/808