Build Smartspace DateWeatherAlarm view the same way as non-flexi

Building the row / column for DateWeatherAlarm in compose doesn't quite
work as expected since alarm has not been seperated out. This change
convert our flexiglass code to match the behavior of SmartspaceSection.

It also adjusts padding for a number of other elements so that they
more closely match the target spec. Mostly this consists of removing
superflous padding, and replacing inline padding numbers with dimension
resource values.

Finally, this change also centers the large clock vertically between the
reserved smartspace region and the lock icon / udfps. There is still an
outstanding where the clock pops to a different y position sometimes,
but that's a different bug.

Bug: 422932152
Bug: 438517594
Test: Checked spacings against previous versions
Flag: com.android.systemui.scene_container
Change-Id: I8dd83faaa956bcbed0697190e988d6fa23fac0cc