remove ipdb again

ipdb doesn't work with capsys and breakpoint

pkgs/clan-app/shell.nix

@@ -21,7 +21,6 @@ let
     ++ (with python3.pkgs; [
       rope
       mypy
-      ipdb
       setuptools
       wheel
       pip
@@ -48,8 +47,6 @@ mkShell {
       desktop-file-utils # verify desktop files
     ]);
 
-  PYTHONBREAKPOINT = "ipdb.set_trace";
-
   shellHook = ''
     export GIT_ROOT=$(git rev-parse --show-toplevel)
     export PKG_ROOT=$GIT_ROOT/pkgs/clan-app

pkgs/clan-cli/shell.nix

@@ -15,7 +15,6 @@ let
       rope
       setuptools
       wheel
-      ipdb
       pip
     ]);
 in
@@ -27,8 +26,6 @@ mkShell {
 
   inputsFrom = [ self'.devShells.default ];
 
-  PYTHONBREAKPOINT = "ipdb.set_trace";
-
   CLAN_STATIC_PROGRAMS = lib.concatStringsSep ":" (
     lib.attrNames clan-cli-full.passthru.runtimeDependenciesAsSet
   );

pkgs/clan-vm-manager/shell.nix

@@ -19,7 +19,6 @@ let
     ++ (with python3.pkgs; [
       rope
       mypy
-      ipdb
       setuptools
       wheel
       pip
@@ -41,8 +40,6 @@ mkShell {
       desktop-file-utils # verify desktop files
     ]);
 
-  PYTHONBREAKPOINT = "ipdb.set_trace";
-
   shellHook = ''
     export GIT_ROOT=$(git rev-parse --show-toplevel)
     export PKG_ROOT=$GIT_ROOT/pkgs/clan-vm-manager