Update Course Search Flash Message Styling and Timeout

Issue Description: When a user submits the Course Search form without entering a course prefix or course number, a message appears stating, “Please enter a course prefix and number.” Currently, this validation message is displayed in green, which makes it look like a success message even though it represents invalid or missing input.

Update the message styling so that validation messages for empty course searches are displayed in red to clearly indicate an error or required action. The message should also automatically disappear after a short period instead of remaining on the page indefinitely.

Expected Behavior:
If a user submits an empty Course Search form, the validation message should appear in red and automatically fade out or disappear after a few seconds.

UI: