fix($compile): allow the usage of "$" in isolate scope property alias

Previously, when using an alias for an isolate scope or `bindings` property
(e.g. `alias: '<attrName'` instead of `attrName: '<'`), a `$compile:iscp` error
was thrown if the attribute name contained a "$".
This commit removes the error by changing the regex to allow "$" characters in
the attribute name when using a property alias.

Fixes: #15586

Closes #15594