Add: Validation for Policy Upload

[BLasan]

Purpose

• Currently, any type of file can be uploaded on a policy creation. Need to restrict the file types to .j2 and .xml

Fixes: wso2/api-manager#2663

[lasanthaS]

Formatting issues

[lasanthaS]

And also this can be simplified as follows.

const handleDrop = (policyDefinition: any) => {
    if (policyDefinition && policyDefinition[0] && (policyDefinition[0].name.endsWith('.j2') || policyDefinition[0].name.endsWith('.xml'))) {
        setPolicyDefinitionFile(policyDefinition);
        return;
    }
    APIMAlert.error(intl.formatMessage({
        id: 'Uploading.Policies.Error',
        defaultMessage: 'Incompatible file type',
    }));
};

[BLasan]

Done

[BLasan]

Will add the backend validation as backend does not return an error on adding an incompatible policy file

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[sonarcloud]

Quality Gate failed

Failed conditions
6.7% Duplication on New Code (required ≤ 3%)

See analysis details on SonarCloud