Fix for issue when importing exported apps

[shnrndk]

Problem:

When the user tries to import the exported application with the keys using apictl, it produces this error.

Error importing Application.
Status: 400
Response: {"code":900970,"message":"Invalid application additional properties","description":"Invalid additional properties. Application configuration values cannot have string values.","moreInfo":"","error":[]}

Public Fix: wso2/api-manager#2087
Master Fix for the the issue: [4.0.0] https://github.com/wso2-enterprise/wso2-apim-internal/issues/4103

Related PRs:

• [4.0.0] https://github.com/wso2-support/carbon-apimgt/pull/6077
• [4.1.0] https://github.com/wso2-support/carbon-apimgt/pull/6087

Test PRs:

• https://github.com/wso2-support/product-apim/pull/1755
• https://github.com/wso2-support/product-apim/pull/1757