On a Mac, I use Alt+Space to insert an invisible character that does the trick. This character is known as a non-breaking space. (
in the HTML encoding; otherwise known as U+00A0. For other platforms, you can copy the character from the code snippet below.)
It's not the same as a normal space. It's an invisible character that looks like a space, and behaves like a space in many contexts, but is a completely distinct character. Git only disallows the normal space character, so it will allow this.
Using this is 100% likely going to confuse the hell out of anyone else and definitely going to bring chaos everywhere, but you can do it if you really want to.
git checkout -b US24024 Automated Tests - Profile A
Switched to a new branch 'US24024 Automated Tests - Profile A'
Note that you cannot copy the character from the above code block (due to a limitation in Stack Overflow). To copy it, run the code snippet below and copy from the text box:
<input type="text" size="1" value=" " style="text-align: center;" readonly>
(Select and copy the contents of this text box.)