Implement getMinLineWidth for LineWidthDelegate

Minikin needs getMinLineWidth() implemented for supporting desperate
breaks in optimal line breaking. This CL implements it for
StaticLayout.

Bug: 68058572
Test: bit CtsTextTestCases:android.text.cts.StaticLayoutLineBreakingTest
Change-Id: I56f6a592c688d816c201279d35fad65e36dffd84