Refactor sender page and auth service logic

- Added project reference to `EnvelopeGenerator.Application` in the client project.
- Updated imports and injected services in `EnvelopeSenderPage.razor`.
- Improved null handling for `EnvelopeReceivers` and updated email display logic.
- Replaced `CheckSenderAsync` with `CheckSenderAccessAsync` for authorization.
- Refactored `GetStatusInfo` to use `EnvelopeStatus` enum directly.
- Added `CheckSenderAccessAsync` and `LogoutSenderAsync` methods in `AuthService`.
- Simplified `Logout` logic in `AuthController` to remove redundant checks.

EnvelopeGenerator.Server/EnvelopeGenerator.Server/Controllers/AuthController.cs

@@ -40,17 +40,11 @@ public partial class AuthController(IOptions<AuthTokenKeys> authTokenKeyOptions,
     /// <response code="401">Wenn es kein zugelassenes Cookie gibt, wird „nicht zugelassen“ zurückgegeben.</response>
     [ProducesResponseType(typeof(void), StatusCodes.Status200OK)]
     [ProducesResponseType(typeof(void), StatusCodes.Status401Unauthorized)]
-    [Authorize(Policy = AuthPolicy.SenderOrReceiver)]
+    [Authorize(Policy = AuthPolicy.Sender)]
     [HttpPost("logout")]
-    public async Task<IActionResult> Logout()
+    public IActionResult Logout()
     {
-        if (await this.IsUserInPolicyAsync(AuthPolicy.Sender))
-            Response.Cookies.Delete(authTokenKeys.Cookie);
-        else if (await this.IsUserInPolicyAsync(AuthPolicy.ReceiverOrReceiverTFA))
-            await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
-        else
-            return Unauthorized();
-
+        Response.Cookies.Delete(authTokenKeys.Cookie);
         return Ok();
     }