[Block Library in DA] Block Description alignment

Currently, the description alignment gets a bit off with more number of entries in block library. Fix needed for description to stay within palette so overflow/hanging description tooltip can be avoided.

Reproduce the issue in the Block Library with many entries and observe how the block descriptions align and how the tooltip extends beyond the palette. Locate the Block Library entry point and the styles or component responsible for description layout; done means descriptions remain within the palette and no overflow or hanging tooltip appears.

Written by the indexing model from the issue text.