recalculate line graph geometry if orientation has changed

[danwood]

Description

Get notified when the orientation changes to force re-calculation of line chart's layout.

Motivation and Context

Currently the line graph doesn't adapt to wider or narrower orientation when you rotate your iPhone/iPad. This change solves that.

How Has This Been Tested?

Tested on iPhone and iPad simulator.

Screenshots (if appropriate):

Types 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 change)
• Non-functional change (Updating Documentation, CI automation, etc..)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.