Fix std::bad_alloc() in WaveformRenderBeat::draw()

[uklotzde]

https://bugs.launchpad.net/mixxx/+bug/1977662
https://bugs.launchpad.net/mixxx/+bug/1959489

@Ronso: Please test if this fixes your issues. Then we could merge it instead of #4787.

[ronso0]

Hehe, build fails because of a typo (in the source, not your code ; )

[ronso0]

Yes, thank you, that also fixes the crash.
Also, having a blank waveform is consistent with the state after

• Mixxx started, no track loaded
• activate passthrough
• load track

compared to the solution in #4787.

Though, the playposition in the overview is still stuck at the center.
I think I'll fix this in the woverview code.

[uklotzde]

Ouch, there is a typo. I tested only the main version.

[ronso0]

Thank you very much, LGTM

[uklotzde]

Merged into main.

[ronso0]

thanks, I got interrupted by real life and was about to do it just now.

[uklotzde]

The new debug assertions unexpectedly triggers on main:

critical [Engine] DEBUG ASSERT: "m_tempo_ratio_old != 0" in function void EngineBuffer::updateIndicators(double, int) at /home/uk/volumes/Build/cpp/mixxx/src/engine/enginebuffer.cpp:1349

 72/786 Test #708: SoundSourceProxyTest.skipAndRead ...........................................................   Passed   59.04 sec