[charts] Refactor optional chaining for props in PieChart, PieChartPro, and ScatterChartPro components

[sai6855]

While working on #19257 i noticed, ?. is used for props where props will always be defined. created PR to remove these instances

[mui-bot]

Deploy preview: https://deploy-preview-19292--material-ui-x.netlify.app/

Bundle size report

Bundle	Parsed size	Gzip size
@mui/x-data-grid	0B(0.00%)	0B(0.00%)
@mui/x-data-grid-pro	0B(0.00%)	▼-1B(0.00%)
@mui/x-data-grid-premium	0B(0.00%)	▼-1B(0.00%)
@mui/x-charts	▼-4B(0.00%)	▼-5B(-0.01%)
@mui/x-charts-pro	▼-7B(0.00%)	▼-13B(-0.01%)
@mui/x-date-pickers	0B(0.00%)	0B(0.00%)
@mui/x-date-pickers-pro	0B(0.00%)	▼-1B(0.00%)
@mui/x-tree-view	0B(0.00%)	0B(0.00%)
@mui/x-tree-view-pro	0B(0.00%)	▼-1B(0.00%)

Details of bundle changes

Generated by 🚫 dangerJS against 26c9279

[codspeed-hq]

CodSpeed Performance Report

Merging #19292 will not alter performance

_{Comparing sai6855:code-clean-charts (26c9279) with master (dbd436e)¹}

Summary

✅ 10 untouched benchmarks

Footnotes

1. No successful run was found on master (d4a395e) during the generation of this report, so dbd436e was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩