fix: Lambda custom policies not working

[osddeitf]

Description of changes

• fix mismatch ajv version between amplify-cli-core and amplify-provider-awscloudformation

Issue #8392

Description of how you validated changes

When I freshly install @aws-amplify/cli@6.3.0 inside node:14-bullseye-slim image, ajv package is in the following folders:

/usr/local/lib/node_modules/npm/node_modules/har-validator/node_modules/ajv
/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/aws-cdk/node_modules/ajv
/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-cli-core/node_modules/ajv
/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/ajv
/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-headless-input/node_modules/ajv

• The amplify-cli-core package use ajv@^6.12.3.
• The module packages/amplify-cli-core/src/customPoliciesUtils.ts export CustomIAMPoliciesSchema.
• The module packages/amplify-provider-awscloudformation/src/pre-push-cfn-processor/cfn-pre-processor.ts use CustomIAMPoliciesSchema with ajv.
• But amplify-provider-awscloudformation has no ajv dependency in its package.json.
• Then it will resolve to use /usr/local/lib/node_modules/@aws-amplify/cli/node_modules/ajv which is in major version 8 (ajv is not a direct dependency of @aws-amplify/cli).
• Result in the error I mentioned in Bug: Lambda custom policies not working #8392;

? Are you sure you want to continue? Yes
strict mode: missing type "object" for keyword "additionalProperties" at "#" (strictTypes)
✖ An error occurred when pushing the resources to the cloud
🛑 
strict mode: unknown keyword: "optionalProperties"
An error occurred during the push operation: strict mode: unknown keyword: "optionalProperties"

• I tried to go to /usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-provider-awscloudformation, run npm install ajv@^6.12.3, then the issue is resolved.

Checklist

• PR description included
• yarn test passes

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

[codecov-commenter]

Codecov Report

Merging #8415 (0933517) into master (bd435e2) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #8415   +/-   ##
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  Coverage   55.92%   55.92%           
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  Files         695      695           
  Lines       38881    38881           
  Branches     7871     7871           
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  Hits        21743    21743           
  Misses      16343    16343           
  Partials      795      795           

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[jhockett]

LGTM, thank you for debugging and opening the PR!