Ability to disable the AWS CLI v2 advertisement in v1

**Is your feature request related to a problem? Please describe.**

A user input error such as a typo results in being spammed at the CLI with a advertisement for AWS CLI version 2. It would be nice if this advertisement could be disabled for those that are unable to move to this version due to current deployment and packaging issues as well as those that provide support for end users that are still using v1.

_Note: AWS CLI version 2, the latest major version of the AWS CLI, is now stable and recommended for general use. For more information, see the AWS CLI version 2 installation instructions at: https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html_

```
$ aws test
Note: AWS CLI version 2, the latest major version of the AWS CLI, is now stable and recommended for general use. For more information, see the AWS CLI version 2 installation instructions at: https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html

usage: aws [options] [ ...] [parameters]
To see help text, you can run:

aws help
aws help
aws help
aws: error: argument command: Invalid choice, valid choices are:

accessanalyzer | acm
```
```
aws ec2 run-instances --profile test --region us-east-1 --image-id ami-xxx --count 1 --instance-type t3.micro \
Note: AWS CLI version 2, the latest major version of the AWS CLI, is now stable and recommended for general use. For more information, see the AWS CLI version 2 installation instructions at: https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html

usage: aws [options] [ ...] [parameters]
To see help text, you can run:

aws help
aws help
aws help

Unknown options:
```
```
$ aws --version
aws-cli/1.18.131 Python/3.8.4 Darwin/18.7.0 botocore/1.17.54
```

**Describe the solution you'd like**

Environment variable or config setting in aws cli v1 to disable the spam note about aws cli v2 being stable