[core] TagInput has wrong focus styling when intent is specified

[tgreen7]

Environment

• Package version(s): core: 3.20.0, select: 3.11.2
• Browser and OS versions: Chrome 78.0.3904.97, MacOS 10.14.6

If possible, link to a minimal repro (fork this code sandbox): https://codesandbox.io/s/blueprint-sandbox-ljjq5

Steps to reproduce

1. Open codesandbox, focus the select input. Highlight changes to blue. Focus the InputGroup. Highlight stays red.

Actual behavior

Highlight changed to blue on intent: "danger" select.

Expected behavior

Highlight should stay red exactly like the InputGroup does

Possible solution

the .bp3-tag-input has the class .bp3-active which sets the box-shadow to blue. It probably needs some .bp3-intent-danger .bp3-active tweaks to keep it red.

[adidahiya]

it seems to be an issue with TagInput in general... updating issue accordingly.