commands: fix "no workspace" and other error paths

Commit 2ac3e27
("WestCommand: use Configuration objects") introduced a
configuration attribute to WestCommand instances, and used
it to look up configuration options.

However, it stored this attribute at the wrong time in
WestCommand.run(). We need to stash the configuration before doing
anything else, because otherwise calls like self.die() in the same
method will look up self.color_ui, which looks up the configuration,
which isn't present, which calls self.die(), leading to an infinite
recursion.

If we stash the configuration immediately, we instead have a valid
configuration option and we get an error printed instead.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>

src/west/commands.py

@@ -182,13 +182,13 @@ def run(self, args: argparse.Namespace, unknown: List[str],
         :param config: `west.configuration.Configuration` or ``None``,
             accessible as ``self.config`` from `WestCommand.do_run`
         '''
+        self.config = config
         if unknown and not self.accepts_unknown_args:
             self.parser.error(f'unexpected arguments: {unknown}')
         if not topdir and self.requires_workspace:
             self.die(_no_topdir_msg(os.getcwd(), self.name))
         self.topdir = os.fspath(topdir) if topdir else None
         self.manifest = manifest
-        self.config = config
         for hook in self._hooks:
             hook(self)
         self.do_run(args, unknown)