fix(issue): Consolidate issue link parsing

[chinesedfan]

Fixes Discovered in #462.

The regular expression can't match anything if issueURL is a issue comment, like https://github.com/octokit/discussions/issues/7#issuecomment-327616339. It causes [1] throws an error.

const issueNumberRegex = /issues\/([0-9]+)$/;
const { issue, issueURL, isPR, language } = navigation.state.params;
const number = issue ? issue.number : issueURL.match(issueNumberRegex)[1];

[machour]

Nice catch buddy, but I think you're fixing another unknown bug here.

#462 is a bug happening when reading an issue. There's no navigation problem related there, but an Animated related exception (see my comments on that issue). If I dismiss the red screen, I do see the issue screen along with some of its comments. The bug there is supposedly with a TouchOpacity element. Still haven't investigate it yet.

[machour]

Ok, I understood what happened here :D

There is the bug reported in #462, which is still un-resolved.
And there's a new bug you spotted by clicking my comment on #462.

[chinesedfan]

@machour Right. I saw the crash you mentioned for a while, but was attracted by this bug. 😆

I have changed the PR description so that this PR doesn't close #462.

[housseindjirdeh]

Thanks a million for this @chinesedfan, and good catch :O :O