Fix empty progress bar

[jacobtomlinson]

Closes #9143

• Calls MultiProgressWidget.make_widget(tasks) even if progress is given an empty iterable of tasks
• If there are no tasks display no tasks given instead of the completion time

[github-actions]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

    27 files  ±0      27 suites  ±0   9h 43m 57s ⏱️ - 2m 31s
 4 112 tests ±0   4 007 ✅ +1    104 💤 ±0  1 ❌  - 1 
51 516 runs  ±0  49 331 ✅ +1  2 184 💤 ±0  1 ❌  - 1 

For more details on these failures, see this check.

Results for commit 236fb27. ± Comparison against base commit c7d9c55.

[jrbourbeau]

Thanks @jacobtomlinson. LGTM overall. Might be worth adding a small test for the empty case but up to you