Tabs within Steps broken on new redesign

[joeyundis-altra]

Description

PR #815 has reintroduced issue #437 which was solved in #440, and as such tabs within steps appear as broken HTML code instead of the expected tab view.

Steps To Reproduce

1. Add a step block
2. Add a set of tabs within that block
3. Observe that the tabs do not function, and show raw code

{{% steps %}}

### Header 1

Text Example

{{< tabs items="Test Tab,Test Tab 2" >}}

{{< tab >}}
#### Test Tab

Test Text

{{< /tab >}}

{{< tab >}}
#### Test Tab 2

Test Text 2

{{< /tab >}}

{{< /tabs >}}

### Header 2

Text Example

{{% /steps %}}

Expected Behavior

Tabs are shown properly within steps

Actual Behavior

Tabs do not show or work correctly

Environment

• Hugo Version: Latest pre-release commits
• Browser/OS: Chrome
• Theme Version: main branch 3551a56