Fix DynamicContainer indexMap update issue

[Kyle-Ye]

Close #567

The root cause is that DynamicContainer is missing updating. So indexMap is nil.

Then DynamicLayoutViewChildGeometry will set its value to .zero.

    func updateValue() {
        guard let index = containerInfo.viewIndex(id: id), index < childGeometries.count else {
            if !hasValue {
                value = .zero
            }
            return
        }
        value = childGeometries[index]
    }

[codecov]

Codecov Report

❌ Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 23.62%. Comparing base (0c0f992) to head (99dae2e).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...nSwiftUICore/Layout/Dynamic/DynamicContainer.swift	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #568      +/-   ##
==========================================
+ Coverage   23.61%   23.62%   +0.01%     
==========================================
  Files         525      525              
  Lines       30470    30472       +2     
==========================================
+ Hits         7195     7199       +4     
+ Misses      23275    23273       -2     

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