Strip whitespace and newlines from access token and style URL

[1ec5]

Just in case browser weirdness or a tendency to triple-click-select is causing some cases of #2012.

Ordinarily we’d want this kind of logic down in mbgl, but I think it belongs up here too because:

• The access token is stored as an instance variable of MGLAccountManager, and I think that ivar should have the correct value too.
• The inspectable style URL string gets transformed into an NSURL in -[MGLMapView setStyleURL__:]. NSURL demands RFC 1738/2732 well-formedness, so if the string has leading whitespace, the transformation will fail and you’ll wind up w/ no URL (and the default style).

/cc @friedbunny

[friedbunny]

Very prudent, thanks for the placement explanation. ❤️

[ljbade]

@1ec5 Can you open similar for Android?

Also does this detect too-short access keys? A person in #2012 mentioned that happened to them.

[1ec5]

Also does this detect too-short access keys? A person in #2012 mentioned that happened to them.

No, and I think any stricter validation belongs in mbgl proper. This PR is only about URL well-formedness.

[1ec5]

The Bitrise test failure is being tracked as #2920. It’s unrelated to this change; merging.