Support periods (.) in custom role names with custom authentication

**Describe the bug**

Adding a role restriction to the routes element in staticwebapp.config.json when the role contains a period (.) fails with the following error:

```
Encountered an issue while validating staticwebapp.config.json: The name of the role Folder.Create.All contains an invalid character.
```

In AAD, it's customary for roles, including app roles, to contain periods, such as in "User.Read." I created an API that reads the roles assigned to the logged in user for the application used by Static Web Apps authentication.

**To Reproduce**

1. In the AAD app registration, define a custom role with periods in the role name.
2. Assign a user to the custom app role.
3. Configure staticwebapp.config.json as shown in the snippet below.
4. Deploy a custom API (/api/Roles) that retrieves custom roles from the claims and returns them.
4. Deploy the app.

Excerpt from staticwebapp.config.json:

```json
"auth": {
"rolesSource": "/api/Roles",
"identityProviders": {
"azureActiveDirectory": {
"registration": {
"openIdIssuer": "https://login.microsoftonline.com/__AZURE_TENANT_ID__/v2.0",
"clientIdSettingName": "AZURE_CLIENT_ID",
"clientSecretSettingName": "AZURE_CLIENT_SECRET"
}
}
}
},
...
{
"route": "/api/TopLevelFolders",
"methods": [
"POST"
],
"allowedRoles": [
"Folder.Create.All"
]
}
```

**Expected behavior**

Custom role names should be able to contain periods to match the common convention found in AAD.