add get_entry and get_entry_without_label to table

[nitzan-treg]

Overview: What does this pull request change?

hey, trying to fix #2051

added two new methods to the Table class -- get_entry(pos) and get_entry_without_label(pos) -- that return a single VMobject at the given position. they just delegate to the existing get_entries and get_entries_without_labels methods so nothing breaks, but now you have dedicated single-entry methods with proper explicit return types instead of the weird union return on the plural methods. the original methods are untouched for backward compat.

Motivation and Explanation: Why and how do your changes improve the library?

Links to added or changed documentation pages

Further Information and Comments

Reviewer Checklist

• The PR title is descriptive enough for the changelog, and the PR is labeled correctly
• If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
• If applicable: newly added functions and classes are tested