Clean comma-separated include paths in grpc_tools

When include paths are passed via the commnad-line, they are passed as
a comma-separated string. This means the user could add extra spaces or
pass a double-comma, which would result in empty strings in the
include paths list, making the protobuf compiler fail.

This commit cleans the include paths by stripping whitespace and
ignoring empty strings.

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

Author: llucax

src/frequenz/repo/config/setuptools/grpc_tools.py

@@ -84,7 +84,9 @@ def run(self) -> None:
         include_paths: Iterable[str]
         match self.include_paths:
             case str() as str_paths:
-                include_paths = str_paths.split(",")
+                # If it comes as a comma-separated string, split it into a list,
+                # stripping whitespace and ignoring empty strings.
+                include_paths = filter(len, map(str.strip, str_paths.split(",")))
             case Iterable() as paths_it:
                 include_paths = paths_it
             case unexpected: