docs: fix typo and use HTTPS for AWS links in README files (#37371)

### Reason for this change

Fix a duplicate word typo and replace `http://` with `https://` for AWS links in README files.

### Description of changes

- `the the` → `the` (aws-ec2-alpha README)
- `http://aws.amazon.com/iam/` → `https://` (aws-cognito-identitypool README)
- `http://aws.amazon.com/cloudwatch/pricing/` → `https://` (aws-ec2 README)
- `http://docs.aws.amazon.com/mediaconvert/` → `https://` (aws-stepfunctions-tasks README)

### Description of how you validated changes

Documentation-only changes. No functional impact.

### 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)

Author: syukawa-gh

packages/@aws-cdk/aws-ec2-alpha/README.md

@@ -584,7 +584,7 @@ You can import an existing VPC and its subnets using the `VpcV2.fromVpcV2Attribu
 
 To import an existing VPC, use the `VpcV2.fromVpcV2Attributes()` method. You'll need to provide the VPC ID, primary CIDR block, and information about the subnets. You can import secondary address as well created through IPAM, BYOIP(IPv4) or enabled through Amazon Provided IPv6. You must provide VPC Id and its primary CIDR block for importing it.
 
-If you wish to add a new subnet to imported VPC, new subnet's IP range(IPv4) will be validated against provided secondary and primary address block to confirm that it is within the the range of VPC.
+If you wish to add a new subnet to imported VPC, new subnet's IP range(IPv4) will be validated against provided secondary and primary address block to confirm that it is within the range of VPC.
 
 Here's an example of importing a VPC with only the required parameters
 

packages/aws-cdk-lib/aws-cognito-identitypool/README.md

@@ -187,7 +187,7 @@ Pools, OpenIdConnect, or SAML. Only one provider per external service can be att
 
 [OpenID Connect](https://docs.aws.amazon.com/cognito/latest/developerguide/open-id.html) is an open standard for  
 authentication that is supported by a number of login providers. Amazon Cognito supports linking of identities with  
-OpenID Connect providers that are configured through [AWS Identity and Access Management](http://aws.amazon.com/iam/). 
+OpenID Connect providers that are configured through [AWS Identity and Access Management](https://aws.amazon.com/iam/). 
 
 An identity provider that supports [Security Assertion Markup Language 2.0 (SAML 2.0)](https://docs.aws.amazon.com/cognito/latest/developerguide/saml-identity-provider.html) can be used to provide a simple  
 onboarding flow for users. The SAML-supporting identity provider specifies the IAM roles that can be assumed by users  

packages/aws-cdk-lib/aws-ec2/README.md

@@ -2638,7 +2638,7 @@ Please note this feature does not support Launch Configurations.
 
 ## Detailed Monitoring
 
-The following demonstrates how to enable [Detailed Monitoring](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-cloudwatch-new.html) for an EC2 instance. Keep in mind that Detailed Monitoring results in [additional charges](http://aws.amazon.com/cloudwatch/pricing/).
+The following demonstrates how to enable [Detailed Monitoring](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-cloudwatch-new.html) for an EC2 instance. Keep in mind that Detailed Monitoring results in [additional charges](https://aws.amazon.com/cloudwatch/pricing/).
 
 ```ts
 declare const vpc: ec2.Vpc;

packages/aws-cdk-lib/aws-stepfunctions-tasks/README.md

@@ -1759,7 +1759,7 @@ Step Functions supports [AWS MediaConvert](https://docs.aws.amazon.com/step-func
 ### CreateJob
 
 The [CreateJob](https://docs.aws.amazon.com/mediaconvert/latest/apireference/jobs.html#jobspost) API creates a new transcoding job.
-For information about jobs and job settings, see the User Guide at http://docs.aws.amazon.com/mediaconvert/latest/ug/what-is.html
+For information about jobs and job settings, see the User Guide at https://docs.aws.amazon.com/mediaconvert/latest/ug/what-is.html
 
 You can call the `CreateJob` API from a `Task` state. Optionally you can specify the `integrationPattern`.