Erroneous `////` in default URL for a blazorwasm template parameter

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Describe the bug

This came up previously with an `appsettings.json` file, but I noticed it while exploring the parameters for the `blazorwasm` template, and I don't think that's been addressed yet.


It appears to me that this was unintentional. I have a fork and branch at the ready for a PR to fix this issue [available here](https://github.com/dotnet/aspnetcore/compare/main...jdmallen:jdmallen/fix-broken-default-url).

### Expected Behavior

I expected a correct and valid URL format to be supplied as a default value that clearly requires one.

### Steps To Reproduce

Repro:
1. Install latest .NET SDK (Host: 6.0.10, SDK: 6.0.402 as of this issue)
1. Execute `dotnet new blazorwasm -h`
1. Scroll down to parameter `--aad-b2c-instance`
1. Note the "Default" value of `https:////aadB2CInstance.b2clogin.com/` verbatim and compare it to other default values on the screen.

### Exceptions (if any)

_No response_

### .NET Version

6.0.402

### Anything else?

It's also worth noting that there's a similar issue with the "replaces" value at [this line](https://github.com/jdmallen/aspnetcore/blob/6d041a013c48f3fa3bd8adeef39f91d730e01830/src/ProjectTemplates/Web.ProjectTemplates/content/ComponentsWebAssembly-CSharp/.template.config/template.json#L389), but since it has a "defaultValue" also configured, the URL with the `////` is not rendered to screen. I can fix that one, too, if you like, but figured I'd keep the commit focused.