Alert visual should have a clear distinction between present & not present

[ccrowley96]

Describe the bug
A clear and concise description of what the bug is.

Request from @rinisbet

As soon as trigger expression for Alerts is != "", the blue badge preview (sans icon, see Alert config feedback in the other chat) should appear on the preview popover... no alert text showing of course until they start typing that

Reasoning: it's a true live view of the badge when the alert is "valid"

To Reproduce
Steps to reproduce the behavior:

1. Go to Alerts tab (in new behavior creation)
2. Enter text in trigger expression box
3. No preview shows of alert configured (color & icon are still null)

Expected behavior
Alerts need default badge / color values. Bottom part of form should probably disappear when no trigger expression is active, indicating alert is not present

Screenshots
Enter text in trigger expression (alert doesn't show)

Select a badge icon (alert shows only badge, no color)

Click on color icon picker (alert shows badge & color)

[ccrowley96]

@rinisbet @msnyder-msft -- logged your alert feedback here Riley to avoid it being lost in chat history