nmcli/edit: fix an assertion failure when tab-completing bad setting name
Attempt to tab-complete a property from a setting which does not exist results in an assertion failure:
nmcli > set lala.lala<TAB>
(process:597363): nm-CRITICAL **: 16:30:21.642: nm_meta_setting_info_editor_find_by_name: assertion 'setting_name' failed
Thread 1 "nmcli" received signal SIGTRAP, Trace/breakpoint trap.
0x00007ffff780dc28 in g_logv () from /lib64/libglib-2.0.so.0
(gdb) bt
#0 0x00007ffff780dc28 in g_logv () at /lib64/libglib-2.0.so.0
#1 0x00007ffff780dea3 in g_log () at /lib64/libglib-2.0.so.0
#2 0x000000000044a2c2 in nm_meta_setting_info_editor_find_by_name (setting_name=<optimized out>, use_alias=use_alias@entry=0)
at src/libnmc-setting/nm-meta-setting-access.c:35
#3 0x000000000042eb07 in get_setting_and_property (prompt=<optimized out>, line=<optimized out>, setting_out=0x7fffffffcf10, property_out=0x7fffffffcf18)
at src/nmcli/connections.c:6639
#4 0x000000000042ec38 in get_allowed_property_values (out_to_free=out_to_free@entry=0x7fffffffcf50) at src/nmcli/connections.c:6711
#5 0x000000000042ed8c in should_complete_property_values (prompt=prompt@entry=0x5befb0 "nmcli 802-1x.pac-file> ", line=line@entry=0x0, multi=multi@entry=0x7fffffffcfe4)
at src/nmcli/connections.c:6735
#6 0x000000000042f5d8 in nmcli_editor_tab_completion (text=0x5bef90 "lala", start=<optimized out>, end=13) at src/nmcli/connections.c:6899
#7 0x00007ffff776dcdc in gen_completion_matches () at /lib64/libreadline.so.8
...
Do not proceed resolving the setting name if it does not pass check_valid_name().