Creating Dynamic Text w/ Map Series that only shows when needed

[Nathan_WeltyNDOT]

I'm working on setting up map layouts in ArcGIS Pro version 3.1.3. These are maps of Counties, and some counties are large enough to require multiple sheets, but most are not. I already set up dynamic text based on the value in the field SheetName to appear on its own line, but I don't want there to be a line there at all if the value in SheetName is null. How would I set it up to have no line? Is there a way to maybe write the expression to have it remove a line if the value is null? Any insight would be appreciated. Thank you!

Here's an example of what we have for counties requiring multiple sheets:

However, here's what happens if I change to another county in the map series, one only requiring one sheet: