Changes to accommodate issue 4632

[rosco54]

1. Unconditionally select default initial axis ticks based on SVG size.
2. Unconditionally, if not user specified, snap yMin or yMax to zero if already close.
3. Re-order yaxes in one sample chart to prioritize stacked column visual resolution. Add comment to draw attention to this feature of multi axis charts.
4. In Scales.niceScale: Check that maxTicks is always valid (suspect some Unit tests don't set SVG dimensions).
5. Set tickAmount explicitly in two unit tests to compensate for variation in scaling following the above changes.

Fixes #4632

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes
• My branch is up to date with any changes from the main branch

[rosco54]

@junedchhipa There are e2e images diff failures that cause the automated checks below to fail. Most are expected but some that I don't expect (like the heatmap diffs). I assume you will be looking at these before accepting the PR. Let me know if there's anything that I need to do at this end please.