chore(glue): support ConnectionType.MARKETPLACE and ConnectionType.CUSTOM (#30395)

### Issue # (if applicable)

N/A

### Reason for this change
`MARKETPLACE` and `CUSTOM` are not supported in the current L2 Construct. (`SFTP` is also missing, but it is not supported at the moment.)

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-glue-connection-connectioninput.html#cfn-glue-connection-connectioninput-connectiontype



### Description of changes
Add missing connection types.



### Description of how you validated changes
I determined that no testing was needed since this was only an addition of connection types.


### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

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

Author: mazyu36

packages/@aws-cdk/aws-glue-alpha/lib/connection.ts

@@ -8,6 +8,8 @@ import { CfnConnection } from 'aws-cdk-lib/aws-glue';
  *
  * If you need to use a connection type that doesn't exist as a static member, you
  * can instantiate a `ConnectionType` object, e.g: `new ConnectionType('NEW_TYPE')`.
+ *
+ * @see https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-glue-connection-connectioninput.html#cfn-glue-connection-connectioninput-connectiontype
  */
 export class ConnectionType {
 
@@ -31,6 +33,18 @@ export class ConnectionType {
    */
   public static readonly NETWORK = new ConnectionType('NETWORK');
 
+  /**
+   * Uses configuration settings contained in a connector purchased from AWS Marketplace
+   * to read from and write to data stores that are not natively supported by AWS Glue.
+   */
+  public static readonly MARKETPLACE = new ConnectionType('MARKETPLACE');
+
+  /**
+   * Uses configuration settings contained in a custom connector to read from and write to data stores
+   * that are not natively supported by AWS Glue.
+   */
+  public static readonly CUSTOM = new ConnectionType('CUSTOM');
+
   /**
    * The name of this ConnectionType, as expected by Connection resource.
    */