MudSimpleTable: Fix missing row borders in nested tables (#11559)

[n0spaces]

Description

Updated _simpletable.scss so the bottom-border: none; rule only applies to immediate child nodes rather than all descendants.

The old selector would apply the rule to all td that descends from tr:last-child, which would cause a nested table to not have row borders if it was in the last row of a MudSimpleTable.

Fixes #11559

How Has This Been Tested?

visually

Type of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation (fix or improvement to the website or code docs)

Code sample:

<MudSimpleTable Dense Outlined Style="width: 300px">
    <tbody>
        <tr>
            <td>foobar</td>
            <td>
                <MudSimpleTable Dense Outlined>
                    <tbody>
                        <tr><td>foo</td><td>1</td></tr>
                        <tr><td>bar</td><td>2</td></tr>
                    </tbody>
                </MudSimpleTable>
            </td>
        </tr>
        <tr>
            <td>foobaz</td>
            <td>
                <MudSimpleTable Dense Outlined>
                    <tbody>
                        <tr><td>foo</td><td>3</td></tr>
                        <tr><td>baz</td><td>4</td></tr>
                    </tbody>
                </MudSimpleTable>
            </td>
        </tr>
    </tbody>
</MudSimpleTable>

Before:

After:

Checklist

• The PR is submitted to the correct branch (dev).
• My code follows the code style of this project.
• I've added relevant tests.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[danielchalmers]

Smart!

[danielchalmers]

@n0spaces #11628 builds on this, would love your thoughts!