Update UI hint directive

[cmata23x3]

Updating the SDK to have consistent hint directive usage as Assistant NLP

For UIHint

• removing unused display_immediately param
• making prompt optional and only including in payload when provided

For AsrHint and UIHint

• updating the text key to be consistent with ANLP usage

[snow0x2d0]

LGTM. You'll need to update the mindmeld dependency to a later version so that tests can run. There's an unpinned dependency that's only fixed in > 4.4.2

[snow0x2d0]

Whoops, looks like this is actually a problem with our actions script. Go ahead and merge this and I'll fix it in another branch.