Loosen vale admin rule to allow new menu option

What does this MR do?

Loosens the vale rule that checks for admin, when we should use the full name. The changes in #333265 (closed) mean we now have a lot more mentions of Admin that are actually valid.

This changes the rule to care about capitalization, so it's looking for admin or Admin. When found, it compares to the valid strings, so Admin would pass, but admin would not. It will fail to find instances of Admin used incorrectly, like "You must have the Admin role", but that's the only solution I found so far. It's better to have loose rules without false positives, than to have a bunch of false positives we can't fix.

• Before change: 326 results, including a mix of both valid ones and false positives.
• After change: 176 results, which should all be valid.

Related issues

#333265 (comment 598761900)

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