doc(cognito): Indicates no region restrictions (#21557)

fixed: #21245  

Remove the statement that it can only be handled in a specific region. Like other services, we will not add a list of regions used.

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packages/@aws-cdk/aws-cognito/lib/user-pool-email.ts

@@ -51,8 +51,6 @@ export interface UserPoolSESOptions {
    * region in which the UserPool is deployed, you must specify that
    * region here.
    *
-   * Must be 'us-east-1', 'us-west-2', or 'eu-west-1'
-   *
    * @default - The same region as the Cognito UserPool
    */
   readonly sesRegion?: string;