fix close button

[chadwhitacre]

The close button for accounts elsewhere was not implemented properly in #2142. Due to the way our CDN is implemented, CSS background URLs need to be specificed relative to the assets/%version directory to work properly in both development and production.

I also switched from _ to - to match existing naming conventions.

[chadwhitacre]

Ping @rummik @seanlinsley @clone1018 @ESWAT.

[seanlinsley]

In the same file we have a url() using /assets/. So... which is right?

[chadwhitacre]

@seanlinsley Good catch. That payments-by class is actually unused at the moment, so I didn't bother updating it. I'm comfortable removing payments-by for now (it came from #2053, which this PR is derived from; we can add it back when needed), but it turns out that there's one other place where we use /assets/. Let me look into that other case ...

[chadwhitacre]

@seanlinsley payments-by dealt with in #2144.

[chadwhitacre]

I've confirmed that the .on-confirm .participant case is indeed broken in production. Since the heart is the old heart anyway I'm going to also update the heart we're using. See also #712.

[chadwhitacre]

Okay @seanlinsley, third and final /assets/ reference fixed in #2145. This chain is ready to go! :-)

[ESWAT]

Hmm OK. I grabbed that image from coinbase branch, so might have to keep this in mind once that's merged (there was another image or two in there).

[chadwhitacre]

@ESWAT Yeah, I think we're good with #2144 and #2145. :-)