Remove Radium from JavalabEditor

Removes Radium from JavalabEditor, which was using it to control some hover state on the carat menu to rename/delete files in the tabbed file header.

As a separate cleanup, it also removes this carat from each tab that is not in use. which saves some real estate in the header. More detail on that change in this thread.

Testing story

In the spirit of providing more detail than "tested manually", here's what my process was. As I moved each property over from the style object, I 1) looked at a javalab allthethings level before making any change, 2) removed the property and observed styling changes, and 3) converted the property to SCSS and observed that the page looked the way that it did before.

@code-dot-org/csa could use your input on whether the change to the tabs when viewing code review (shown in the Slack thread linked in the description) is acceptable. FWIW, I think getting rid of the carats is an upgrade, and we could look into improving how the tabs look in code review later if we wanted.

uh oh, have some unexpected commits appearing here. looking into it...

uh oh, have some unexpected commits appearing here. looking into it...

Fixed!

@madelynkasula @sanchitmalhotra126 could you give this one more look? After merging in Sanchit's refactor changes to JavalabEditor, I realized we were pretty close to fully removing the styles object, so I went ahead and did it (hopefully) 🙌

how do we feel about where a CSS module file should reside? Should it be alongside the file it references? Or should it be in some sort of /styles/ sub directory?

@sanchitmalhotra126 right now, we're having modules reside in the same directory as the component that uses it