[lldb][NFCI] Remove CommandReturnObject from BreakpointIDList (#77858)

BreakpointIDList does not need to know about CommandReturnObject.
BreakpointIDList::FindAndReplaceIDRanges is the last place that uses it
in BreakpointIDList.

Instead of passing in a CommandReturnObject, it now returns an
llvm::Error. The callsite uses the Error to populate the
CommandReturnObject as needed.