Fix/oscilloscope background load

[nitin710]

Description

• Adds a check to make sure the image exists at the location provided for the background image.

Requirements

• None

Issues Referenced

• Oscilloscope crashes if the image file does not exist at the path provided.

Documentation update

Link to a change in documentation (if any)

Testing

Feature Tests (Integration tests)

Feature Test	Result
Warning printed in console if image does not exist	✔️

[nitin710]

The way ofImage::load works, it handles image not present, so a absense of the image file will not crash the oscilloscope.