Use normalized CachedDisplayInfo as key

- For system Launcher, migrate to use getPossibleMaximumWindowMetrics instead of getDisplays
- Removed usage of displayId
- In estimateInternalDisplayBounds, use CachedDisplayInfo directly as a key
- When cache retunrs null for the current display (e.g. the 3P launcher case), invalidate the cache and estimate again, and only add to supportedBounds if current display is not found in the new cache

Bug: 227459045
Bug: 198965093
Test: manual
Change-Id: Ibcc05ba483ed31a40d16e3cf49c3f3d43af68cf6