Add AllowRepeats to SBCommandInterpreterRunOptions. (#94786)

This is useful if you have a transcript of a user session and want to
rerun those commands with RunCommandInterpreter. The same functionality
is also useful in testing.

I'm adding it primarily for the second reason. In a subsequent patch,
I'm adding the ability to Python based commands to provide their
"auto-repeat" command. Among other things, that will allow potentially
state destroying user commands to prevent auto-repeat. Testing this with
Shell or pexpect tests is not nearly as accurate or convenient as using
RunCommandInterpreter, but to use that I need to allow auto-repeat.

I think for consistency's sake, having interactive sessions always do
auto-repeats is the right choice, though that's a lightly held
opinion...