Make Pretty Formats More Efficient by Squashing Consecutive Blocks

Make Pretty formats prettier: squash blocks if not much time passed since the output of the previous block. This is controlled by new settings output_format_pretty_squash_consecutive_ms (50 ms by default) and output_format_pretty_squash_max_wait_ms (1000 ms by default). Continuation of #49537. This closes #49153. #73852 (Alexey Milovidov).