fix(cognito): remove invalid SES region check (#17868)

When configuring the Cognito SES email integration we were performing a
region check to make sure you were configuring SES in one of the 3
supported regions. This was based on the Cognito documentation [here](https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-email.html#user-pool-email-developer)
which is not correct. This PR removes that check allowing CloudFormation
to provide the validation. If a user provides an incorrect region the
CloudFormation deployment will fail with a descriptive error message.

fixes #17795


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: corymhall

packages/@aws-cdk/aws-cognito/README.md

@@ -349,7 +349,7 @@ new cognito.UserPool(this, 'myuserpool', {
 });
 ```
 
-Sending emails through SES requires that SES be configured (as described above) in one of the regions - `us-east-1`, `us-west-1`, or `eu-west-1`.
+Sending emails through SES requires that SES be configured (as described above) in a valid SES region.
 If the UserPool is being created in a different region, `sesRegion` must be used to specify the correct SES region.
 
 ```ts

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

@@ -2,11 +2,6 @@ import { Stack, Token } from '@aws-cdk/core';
 import { Construct } from 'constructs';
 import { toASCII as punycodeEncode } from 'punycode/';
 
-/**
-  * The valid Amazon SES configuration regions
-  */
-const REGIONS = ['us-east-1', 'us-west-2', 'eu-west-1'];
-
 /**
  * Configuration for Cognito sending emails via Amazon SES
  */
@@ -164,12 +159,6 @@ class SESEmail extends UserPoolEmail {
       throw new Error('Your stack region cannot be determined so "sesRegion" is required in SESOptions');
     }
 
-    if (this.options.sesRegion && !REGIONS.includes(this.options.sesRegion)) {
-      throw new Error(`sesRegion must be one of 'us-east-1', 'us-west-2', 'eu-west-1'. received ${this.options.sesRegion}`);
-    } else if (!this.options.sesRegion && !REGIONS.includes(region)) {
-      throw new Error(`Your stack is in ${region}, which is not a SES Region. Please provide a valid value for 'sesRegion'`);
-    }
-
     let from = this.options.fromEmail;
     if (this.options.fromName) {
       from = `${this.options.fromName} <${this.options.fromEmail}>`;

packages/@aws-cdk/aws-cognito/test/user-pool.test.ts

@@ -1701,48 +1701,8 @@ describe('User Pool', () => {
       },
     });
 
-  });
-  test('email withSES invalid region throws error', () => {
-    // GIVEN
-    const stack = new Stack(undefined, undefined, {
-      env: {
-        region: 'us-east-2',
-        account: '11111111111',
-      },
-    });
-
-    // WHEN
-    expect(() => new UserPool(stack, 'Pool', {
-      email: UserPoolEmail.withSES({
-        fromEmail: 'mycustomemail@example.com',
-        fromName: 'My Custom Email',
-        replyTo: 'reply@example.com',
-        configurationSetName: 'default',
-      }),
-    })).toThrow(/Please provide a valid value/);
-
   });
 
-  test('email withSES invalid sesRegion throws error', () => {
-    // GIVEN
-    const stack = new Stack(undefined, undefined, {
-      env: {
-        account: '11111111111',
-      },
-    });
-
-    // WHEN
-    expect(() => new UserPool(stack, 'Pool', {
-      email: UserPoolEmail.withSES({
-        sesRegion: 'us-east-2',
-        fromEmail: 'mycustomemail@example.com',
-        fromName: 'My Custom Email',
-        replyTo: 'reply@example.com',
-        configurationSetName: 'default',
-      }),
-    })).toThrow(/sesRegion must be one of/);
-
-  });
 });
 
 test('device tracking is configured correctly', () => {