chore(integ-tests): revert add waiterProvider to IApiCall (aws#28457)

Reverts aws#27844. This change broke the pipeline, pacmak fails with:

```
#STDOUT> /tmp/npm-packu6YRYj/Amazon.CDK.IntegTests.Alpha/Amazon/CDK/IntegTests/Alpha/ApiCallBase.cs(231,77): error CS0115: 'ApiCallBase._Proxy.WaiterProvider': no suitable method found to override [/tmp/npm-packu6YRYj/Amazon.CDK.IntegTests.Alpha/Amazon.CDK.IntegTests.Alpha.csproj]
```

packages/@aws-cdk/integ-tests-alpha/README.md

@@ -522,32 +522,3 @@ const describe = testCase.assertions.awsApiCall('StepFunctions', 'describeExecut
 });
 ```
 
-When `waitForAssertions()` is used for the `awsApiCall`, the actual API call is executed
-by the `waiterProvider` assertion provider.
-
-By default, the `AwsApiCall` construct will automatically add the correct IAM policies
-to allow the Lambda function to make the API call. It does this based on the `service`
-and `api` that is provided. In the above example the service is `SQS` and the api is
-`receiveMessage` so it will create a policy with `Action: 'sqs:ReceiveMessage`.
-
-There are some cases where the permissions do not exactly match the service/api call, for
-example the S3 `listObjectsV2` api. In these cases it is possible to add the correct policy
-by accessing the `waiterProvider` object.
-
-```ts
-declare const integ: IntegTest;
-
-const apiCall = integ.assertions.awsApiCall('S3', 'listObjectsV2', {
-  Bucket: 'mybucket',
-}).waitForAssertions({
-  totalTimeout: Duration.minutes(5),
-  interval: Duration.seconds(15),
-  backoffRate: 3,
-});
-
-apiCall.waiterProvider?.addToRolePolicy({
-  Effect: 'Allow',
-  Action: ['s3:GetObject', 's3:ListBucket'],
-  Resource: ['*'],
-});
-```

packages/@aws-cdk/integ-tests-alpha/lib/assertions/api-call-base.ts

@@ -9,8 +9,8 @@ import { WaiterStateMachineOptions } from './waiter-state-machine';
  */
 export interface IApiCall extends IConstruct {
   /**
-   * Access the AssertionsProvider. This can be used to add additional IAM policies
-   * to the provider role policy.
+   * access the AssertionsProvider. This can be used to add additional IAM policies
+   * the the provider role policy
    *
    * @example
    * declare const apiCall: AwsApiCall;
@@ -22,21 +22,6 @@ export interface IApiCall extends IConstruct {
    */
   readonly provider: AssertionsProvider;
 
-  /**
-   * Access the AssertionsProvider for the waiter state machine.
-   * This can be used to add additional IAM policies
-   * to the provider role policy.
-   *
-   * @example
-   * declare const apiCall: AwsApiCall;
-   * apiCall.waiterProvider?.addToRolePolicy({
-   *   Effect: 'Allow',
-   *   Action: ['s3:GetObject'],
-   *   Resource: ['*'],
-   * });
-   */
-  readonly waiterProvider?: AssertionsProvider;
-
   /**
    * Returns the value of an attribute of the custom resource of an arbitrary
    * type. Attributes are returned from the custom resource provider through the