[lldb] [debugserver] fix qLaunchSuccess error, add QErrorStringInPacketSupported (#82593)

Pavel added an extension to lldb's gdb remote serial protocol that
allows the debug stub to append an error message (ascii hex encoded)
after an error response packet Exx. This was added in 2017 in
https://reviews.llvm.org/D34945 . lldb sends the
QErrorStringInPacketSupported packet and then the remote stub may add
these error strings.

debugserver has two bugs in its use of extended error messages: the
vAttach family would send the extended error string without checking if
the mode had been enabled. And qLaunchSuccess would not properly format
its error response packet (missing the hex digits, did not asciihex
encode the string).

There is also a bug in the HandlePacket_D (detach) packet where the
error packets did not include hex digits, but this one does not append
an error string.

I'm adding a new RNBRemote::SendErrorPacket() and routing all error
packet returns though this one method. It takes an optional second
string which is the longer error message; it now handles appending it to
the Exx response or not, depending on the QErrorStringInPacketSupported
state. I updated all packets to send their errors via this method.

Author: jasonmolenda