command: reduce OSC/stats log spam

For some inexplicable reason, the OSC runs the expand-text command a
_lot_. This command is logged at the log file default log level, so the
log file can quickly fill up with these messages. It directly violates
the mpv logging policy: per-frame (or similarly common) log messages
should not be enabled by default for the log file.

stats.lua uses the show-text command for some reason (instead of
creating its own OSD layer).

Explicitly reduce the log level for expand-text and some other commands.
Also reduce the log level for commands triggered by mouse movement.

The previous commit also contributed some to reduce log spam.

Fixes: #4771

input/cmd.h

@@ -40,6 +40,7 @@ struct mp_cmd_def {
     bool vararg;        // last argument can be given 0 to multiple times
     bool scalable;
     bool is_ignore;
+    bool is_noisy;      // reduce log level
     bool default_async; // default to MP_ASYNC flag if none set by user
     // If you set this, handler() must ensure mp_cmd_ctx_complete() is called
     // at some point (can be after handler() returns). If you don't set it, the