Add implicit string-to-Permission conversion operator

Added an implicit conversion operator to the `Permission` struct
to allow a `string` to be implicitly converted to a `Permission`
instance. This complements the existing conversion operator for
`Permission` to `string`, enabling seamless two-way conversion
between `Permission` and `string`. Improves usability by removing
the need for explicit conversion methods.

Author: vp

src/Common.Abstractions/Authorization/Permission.cs

@@ -111,4 +111,9 @@ public bool Equals(Permission other)
     /// Implicitly converts the permission to its string representation.
     /// </summary>
     public static implicit operator string(Permission permission) => permission.value;
+
+    /// <summary>
+    /// Implicitly converts a string to a permission.
+    /// </summary>
+    public static implicit operator Permission(string value) => new(value);
 }