[cards] Fix config issue permanently.

[valayDave]

• Ensures configs behave consistently with cards.
  Testing script to see it works :

from metaflow import FlowSpec, step, card, current, Config
from metaflow.cards import ProgressBar

def git_info(args=None):
    from subprocess import check_output, CalledProcessError

    info = {
        "commit": ["git", "rev-parse", "HEAD"],
        "branch": ["git", "rev-parse", "--abbrev-ref", "HEAD"],
        "message": ["git", "log", "-1", "--pretty=%B"],
        "remote": ["git", "config", "--get", "remote.origin.url"],
    }
    cfg = {}
    try:
        for key, cmd in info.items():
            cfg[key] = check_output(cmd, text=True).strip()
    except CalledProcessError as e:
        # Handle cases where git commands fail
        cfg["error"] = f"Git command failed: {e}"
    return cfg


class PythonCodeDemoFlow(FlowSpec):

    git_info = Config("git_info", default_value="", parser=git_info)

    @card
    @card(type="blank", id="progress_bar", customize=True)
    @step
    def start(self):
        import time
        progress = ProgressBar(max=100)

        current.card.append(progress)
        for i in range(100):
            progress.update(i)
            current.card.refresh()
            time.sleep(1)
        
        self.next(self.end)

    @step
    def end(self):
        pass

if __name__ == '__main__':
    PythonCodeDemoFlow()

[valayDave]

Earlier we were naively removing the config file when the same config file is referenced for all CardCreators. So this broke configs when many cards are present.

[valayDave]

Now we only remove the config when all the decorators are either done with task_finished or with task_exception

[romain-intel]

nit: would move this to a function (it's called twice).

[romain-intel]

Minor nit but LGTM otherwise.