ui: Use curly quotes in UI strings

[chrisbobbe]

If we think it's more polished, we should consistently use curly quotes instead of straight quotes in UI strings. We use curly quotes in zulip-mobile, and in fact tools/test intl helps us enforce that.

So for example, use this:

Please tap “{troubleshootingPageTitle}” for more details.

not this:

Please tap "{troubleshootingPageTitle}" for more details.

And use this:

What’s your status?

not this:

What's your status?

[Aman-Sirmaur19]

@zulipbot claim

[chrisbobbe]

Please take a look at the Zulip project's guide to getting involved with the code:

https://zulip.readthedocs.io/en/latest/contributing/contributing.html#your-first-codebase-contribution
https://zulip.readthedocs.io/en/latest/contributing/contributing.html#picking-an-issue-to-work-on