[PM-21179] Add interface to check if user is enrolled in account recovery (#6993)

* Add validation for reset password key and account recovery enrollment in OrganizationUser

* Update admin approval logic to check account recovery enrollment and add tests for reset password key validation

* Enhance UserService validation to include account recovery enrollment and add unit test for empty or whitespace reset password key handling

* Refactor OrganizationUserUserDetailsQuery to validate reset password keys and add unit tests for filtering out invalid keys

* Update AdminRecoverAccountCommand to validate account recovery enrollment and adjust tests for whitespace reset password keys

* Enhance OrganizationUserRotationValidator to validate reset password keys, including filtering out whitespace-only keys, and add corresponding unit tests for validation logic.

* Refactor OrganizationUserUserDetailsQueryTests to remove unnecessary whitespace-only test cases for account recovery key validation.

* Refactor MemberResponseModel to use OrganizationUser's validation method for ResetPasswordEnrolled status and update corresponding unit test for clarity.

* Refactor OrganizationUsersController and response models to utilize OrganizationUser's validation method for ResetPasswordKey, ensuring consistent validation across the application. Add unit tests for OrganizationUser to verify key validation logic.

* Update OrganizationUserRotationValidator to handle null reset password keys and adjust tests for client-side bug. Add comments for future migration after resolving PM-31001.

* Fix whitespace issue in UserServiceTests.cs by removing BOM character from the file header.

test/Core.Test/AdminConsole/Entities/OrganizationUserTests.cs

@@ -0,0 +1,38 @@
+using Bit.Core.Entities;
+using Xunit;
+
+namespace Bit.Core.Test.AdminConsole.Entities;
+
+public class OrganizationUserTests
+{
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData(" ")]
+    public void IsValidResetPasswordKey_InvalidKeys_ReturnsFalse(string? resetPasswordKey)
+    {
+        Assert.False(OrganizationUser.IsValidResetPasswordKey(resetPasswordKey));
+    }
+
+    [Fact]
+    public void IsValidResetPasswordKey_ValidKey_ReturnsTrue()
+    {
+        Assert.True(OrganizationUser.IsValidResetPasswordKey("validKey"));
+    }
+
+    [Fact]
+    public void IsEnrolledInAccountRecovery_NullKey_ReturnsFalse()
+    {
+        var orgUser = new OrganizationUser { ResetPasswordKey = null };
+
+        Assert.False(orgUser.IsEnrolledInAccountRecovery());
+    }
+
+    [Fact]
+    public void IsEnrolledInAccountRecovery_ValidKey_ReturnsTrue()
+    {
+        var orgUser = new OrganizationUser { ResetPasswordKey = "validKey" };
+
+        Assert.True(orgUser.IsEnrolledInAccountRecovery());
+    }
+}