docs(docs-infra): Typo in first-app-lesson-04.md
fix an error in the description of Step 3 paragraph 5:
instead of
"If the data didn't satisfy the description of the IF the IDE has enough information to give us helpful errors."
the correct text is now
"If the data didn't satisfy the description of the INTERFACE, the IDE has enough information to give us helpful errors."
PR Close#51021
Adds the content for lesson 07, a new image, a navigation entry and some updates to the example code for this lesson. Also, this updates previous lessons where typos and copy/pasta errors show up
PR Close#49980
Each individual lesson should have the images available in the download since a learner can start from any lesson. So, we're adding images here. Also, sync'ing styles for consistency across the lessons. This is fixing some previous commits that didn't include these changes. The goal is that for future commits we can have less changes and focused solely on that lesson
PR Close#49980
Update the tutorial for lesson 04 on interfaces. Also added images required for the base app. Created the placeholder for the next lesson so the app works if built from this branch. Updated navigation to include this step in the navigation menu.
PR Close#49980
