Empty nimble-table is missing horizontal scrollbar

[mollykreis]

🐛 Bug Report

The nimble table with no data can end up without a horizontal scrollbar even when all the columns do not fit within the width of the table.

For example, in the screenshot below the columns are clipped but no scrollbar is present:

💻 Repro or Code Sample

🤔 Expected Behavior

When the columns don't all fit in the width of the nimble-table, a horizontal scrollbar should be present, regardless of whether or not there are any rows of data in the table.

😯 Current Behavior

The table can get into a state where a horizontal scrollbar isn't present when there is no data in the table.

To reproduce in nimble's storybook:

1. Open a table story (not the docs page), such as https://nimble.ni.dev/storybook/?path=/story/components-table--table
2. Reduce the width of your browser window to make the table have a horizontal scrollbar
3. In dev tools, clear the data in the table
4. Notice that the horizontal scrollbar disappears

💁 Possible Solution

🔦 Context

🌍 Your Environment

• OS & Device: [e.g. MacOS, iOS, Windows, Linux] on [iPhone 7, PC]
• Browser [e.g. Microsoft Edge, Google Chrome, Apple Safari, Mozilla FireFox]
• Version [e.g. 1.8.0]