Fix SVG scaling on fullscreen mode for st.graphviz_chart

[snehankekre]

Describe your changes

This PR addresses the scaling issues associated with GraphVizChart when in and exiting fullscreen mode.

Problem

When entering fullscreen with st.graphviz_chart:

1. The SVG remained constant in width and height, but the parent div container StyledGraphVizChart scaled to fullscreen dimensions. (i.e. the chart is not actually fullscreen)
2. Exiting fullscreen led the SVG to adopt the fullscreen dimensions while the container div reverted to its original size. This caused the SVG to appear disproportionately large with excessive vertical space.

Solution:

This PR ensures consistent scaling for both the parent div container and the SVG element:

1. On entering fullscreen, both the SVG and its parent div scale to fullscreen dimensions.
2. Exiting fullscreen mode restores both the SVG and the parent div to their original dimensions.

GitHub Issue Link (if applicable)

Closes #6527.

Testing Plan

• Updated unit test
• Added and migrated e2e tests from cypress to playwright.

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Contribution License Agreement

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