Remove $cookieStore (deprecated since 1.4.0)

[mgol]

I'm submitting a ...

• bug report
• feature request
• other
  A removal of a deprecated API.

Current behavior:

$cookieStore still exists even though it's been deprecated since 1.4.0.

Expected / new behavior:

$cookieStore shouldn't exist.

Minimal reproduction of the problem with instructions:

AngularJS version: 1.6.9

Browser: all

Anything else:

[Narretz]

Done in 73c6467

[mgol]

Oops, I forgot about the issue.

This was done in PR #16465.