Configure mco console plugin web server to use recommended MIME type

[SanjalKatiyar]

Severity: Medium
Priority: Low

Current behaviour (checked on OCP/MCO 4.15):
Request URL: https://<OCP_BASE_URL>/api/plugins/odf-multicluster-console/exposed-features-chunk.js

Response headers:

content-type: application/javascript
x-content-type-options: nosniff

application/javascript is considered to be a legacy JavaScript MIME type but is still a valid one for now. Proper MIME type for JavaScript according to current HTML spec is text/javascript.

Refer: openshift/console#13637 (comment) for more details.