[Bug] Incrementing pitch number fails before any note is played

[macayu17]

Description

Using add 1 to with the pitch number block before the turtle has played a note fails.

MyPitchBlock.setter() assumes tur.singer.lastNotePlayed exists, but it is null before the first note. The setter then tries to read lastNotePlayed[1].

Expected Behavior

The pitch number should initialize and increment successfully even when no note has been played yet.

Screenshots

Not applicable.

How to Reproduce

A source-level reproduction is currently confirmed:

1. Set tur.singer.lastNotePlayed to null.
2. Invoke MyPitchBlock.setter().

The setter accesses tur.singer.lastNotePlayed[1] and throws.

Console log Errors

TypeError: Cannot read properties of null (reading '1')
    at MyPitchBlock.setter

Environment

• Browser: Google Chrome 151
• Node.js: v22.22.3
• Version of Software/Project: current master (b48c67a)

Checklist

• I have read and followed the project's code of conduct.
• I have searched for similar issues before creating this one.
• I have provided all the necessary information to understand and reproduce the issue.
• I am willing to contribute to the resolution of this issue.