Fix behaviors of gui.sidePanelWidth: 1

[ChrisMcD1]

• PR Description

We have technically allowed sidePanelWidth = 1 in the schema for forever. But it seems it never worked! #4582

yaml:"sidePanelWidth" jsonschema:"maximum=1,minimum=0"

This PR fixes 2 behaviors:

1. When trying to full screen the main view, we previously we were relying on setting just the sideSectionWeight in order to ensure the main panel was fully focused. This can cause a problem if the user had their gui.sidePanelWidth set to 1. Such a value make the mainPanelWidth = 0 by default. By just setting the sideSectionWeight, you then communicate to the UI that you want both halves of the screen to have 0 width! No good! Crash!
2. When switching to the main view, we implicitly assumed it was visible. Now, we set it to be full screen if it otherwise would have been not-rendered. That feels like the natural behavior for a full-screen side panel user.

These changes seem like they won't impact users of more standard gui.sidePanelWidth values, so it's just a free win!

Fixes #4582

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[stefanhaller]

The changes make sense to me. I guess there are some more weirdnesses around focusing the main view in half or full screen mode, but I don't use these modes much, and can't be bothered right now to explore this more. 😄

We have fancy tests for this kind of stuff in window_arrangement_helper_test.go, do you think it's worth adding tests for these new conditions?

[ChrisMcD1]

We have fancy tests for this kind of stuff in window_arrangement_helper_test.go, do you think it's worth adding tests for these new conditions?

Sure, just added! Those tests don't end up exercising the crash point that created this PR, so I also made an integration test for that behavior in particular.

I also realized I had inadvertently duplicated the logic of "make the main view full screen", so I added a fixup to simply that logic.

[stefanhaller]

Looks great. Just one last question about the integration test: I verified that it crashes when I revert the production code changes, but only if I run it with go test pkg/integration/clients/*.go. If I run it with go run cmd/integration_test/main.go cli ui/side_panel_width_1, then it succeeds. Any idea why that might be?