Janitorial: Fix all ESLint errors

[brbrr]

In #11095 we disabled bunch of rules due to fixing complexity of these errors. We should re-visit these rules and fix issues incrementally. Or just ignore them :)

List of disabled rules:

"wpcalypso/redux-no-bound-selectors": 0,
"jsx-a11y/anchor-has-content": 0,
"react/no-string-refs": 0,
"jsx-a11y/anchor-is-valid": 0,

[stale]

This issue has been marked as stale. This happened because:

• It has been inactive in the past 6 months.
• It hasn’t been labeled `[Pri] Blocker`, `[Pri] High`.

No further action is needed. But it's worth checking if this ticket has clear reproduction steps and it is still reproducible. Feel free to close this issue if you think it's not valid anymore — if you do, please add a brief explanation.

[brbrr]

Unstale

[stale]

This issue has been marked as stale. This happened because:

• It has been inactive in the past 6 months.
• It hasn’t been labeled `[Pri] Blocker`, `[Pri] High`.

No further action is needed. But it's worth checking if this ticket has clear reproduction steps and it is still reproducible. Feel free to close this issue if you think it's not valid anymore — if you do, please add a brief explanation.