courses: aligned step buttons

[uj-sxn]

This PR (issue #9532 ) improves the layout of the Edit Course step interface by ensuring the action buttons (Update Test, Add Resource, Add Survey, and Add Step) are consistently aligned along a single horizontal baseline at the bottom right of the container.

Changes made:

• Added class="step-actions" to the
  in courses-step.component.html
• Introduced flexbox styling in courses-step.component.scss to:
• Force display: flex with justify-content: flex-end for right alignment
• Set gap: 8px for reduced, consistent spacing between buttons
• Remove unwanted margins/padding and override any conflicting directive styles with !important where needed
• Eliminate potential left border/vertical line artifact

Screenshot: