Making changes for mlb_pbp function

[spencerlin-ysl]

Description

Fixes play-by-play data retrieval for Rookie level games.

Problem

The mlb_pbp() function was failing for most of the Rookie level games because the API returns a different data structure. Specifically:

• Rookie level games don't have endTime on every pitch

Solution

• Add conditional logic to detect Rookie level games
• Use the fact that the playId field has a different structure that encodes the atBatIndex
• Extract atBatIndex from the playId structure (characters 11-12)
• Remove overlapping columns before join to prevent conflicts
• Filter out NA values to prevent warnings