Fix layout overflow issue in DAG Details Logs tab

[Revanth14]

Description

Fixes the details panel where the header, breadcrumb, and action buttons disappear when task logs (or any tab content) is longer than the viewport.

Problem

Improper height handling in nested flex containers caused tab content (such as Logs) to expand beyond its intended bounds. When content exceeded the viewport height, the page-level layout scrolled in a way that hid the header and action controls.

Fix

• Applied correct flex layout rules (flex={1}, minH={0})
• Restored explicit height="100%" where required for Graph and Gantt rendering
• Ensured contained scroll behavior without affecting page-level scroll

Testing

• Manual verification in Logs, Graph, and Gantt tabs
• Frontend tests passing
• Static checks passing

Before

After

After scrolling the full page

Fixes #63934

[boring-cyborg]

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