Fix base-path reference

[aws-asolidu]

Issue #, if available:

Description of changes:
There was a bug where the static assets were unable to load if CE was being served from a custom root endpoint such as /codeeditor/default.

This was caused by a reference to the wrong base-path variable name. It was server-base-path when it should of have been base-path

• These changes will not break the local running of CE (outside SM). Verified by running the application locally.

Testing
I've tested locally and on SM Studio by ensuring the static assets were being loaded successfully

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