RequestDelegateGenerator requires the object to implement `IParsable<T>` or otherwise have a `TryParse` method.

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Describe the bug

With the `RequestDelegateGenerator` enabled (`PublishAoT` or `EnableRequestDelegateGenerator` to `true`), minimal api endpoints with `[FromForm]` on a model without a custom-made `TryParse` method will not compile correctly.

`[FromBody]` - which I imagine would work more-or-less the same in this regard - does not have this issue.

Note: I have not tested whether these actually _work_ for `[FromBody]` (or any of the other ones, for that matter), but the generated code _compiles_ for all but the two non-`TryParsable` `[FromForm]`-based endpoints.

### Expected Behavior

`[FromForm]` and `[FromBody]` should work identically, and should not require the developer to create their own `TryParse` method.

### Steps To Reproduce

https://github.com/KennethHoff/Repros/tree/66a2d8c3b53fd64dfc5f3880cb2db8d9cac6550a/AspNetCoreRequestDelegateGenerator

### Exceptions (if any)

#### On .Net 8 (All compiler versions mentioned below):

```
0>GeneratedRouteBuilderExtensions.g.cs(520,59): Error CS0029 : Cannot implicitly convert type 'string' to 'NotParsableForm'
0>GeneratedRouteBuilderExtensions.g.cs(551,59): Error CS0029 : Cannot implicitly convert type 'string' to 'NotParsableForm'
0>GeneratedRouteBuilderExtensions.g.cs(637,67): Error CS0029 : Cannot implicitly convert type 'string' to 'ImplicitlyParseOnlyForm'
0>GeneratedRouteBuilderExtensions.g.cs(668,67): Error CS0029 : Cannot implicitly convert type 'string' to 'ImplicitlyParseOnlyForm'
```

#### On .Net 9 (With `9.0.100-preview.1.24101.2`):

```
0>GeneratedRouteBuilderExtensions.g.cs(526,59): Error CS0029 : Cannot implicitly convert type 'string' to 'NotParsableForm'
0>GeneratedRouteBuilderExtensions.g.cs(557,59): Error CS0029 : Cannot implicitly convert type 'string' to 'NotParsableForm'
0>GeneratedRouteBuilderExtensions.g.cs(645,67): Error CS0029 : Cannot implicitly convert type 'string' to 'ImplicitlyParseOnlyForm'
0>GeneratedRouteBuilderExtensions.g.cs(676,67): Error CS0029 : Cannot implicitly convert type 'string' to 'ImplicitlyParseOnlyForm'
```

### .NET Version

Tested with all the following versions:
`8.0.100`, `8.0.201`, `9.0.100-preview.1.24101.2`

### Anything else?

This was tested on Linux, but I have also experienced the general premise (`cannot implicitly convert type 'string' to ''` with `[FromForm]` on Windows.

_No response_