Preview offset after switch fix choco butter ui

Changes
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1. Refactored InfoBubbleViewModel (IBVM) to stabilize it and remove ambiguity
2. Shifted initial value set up to constructor of IBVM to centralize everything.
3. Added an on_load event handler to InfoBubbleView to set up initial environment.
    This also resolves a bug that causes preview bubbles to show up when switching between tabs. (MAGN-810)