cmd/git(fix[remote show]): Only add --verbose when explicitly True

why: Using `if verbose is not None:` would add --verbose for both
True and False values. The flag should only be added when verbose=True.
what:
- Change `if verbose is not None:` to `if verbose is True:` in
  GitRemoteCmd.show() and GitRemoteManager.show()

Author: tony

src/libvcs/cmd/git.py

@@ -3811,7 +3811,7 @@ def show(
         local_flags: list[str] = []
         required_flags: list[str] = [self.remote_name]
 
-        if verbose is not None:
+        if verbose is True:
             local_flags.append("--verbose")
 
         if no_query_remotes:
@@ -4305,7 +4305,7 @@ def show(
         if name is not None:
             required_flags.append(name)
 
-        if verbose is not None:
+        if verbose is True:
             local_flags.append("--verbose")
 
         if no_query_remotes: