Align pie charts to card centers in Analytics pages

chart-pie elements of nuxeo-cards found in Analytics pages (such as nuxeo-repository-analytics) are left-aligned while resizing the browser window - they should remain center aligned as seen when first opening the page fully maximized, and respond correctly to resizing the browser.

Steps to Reproduce:

1. In Web UI, navigate to Administration > Analytics > Repository Content
2. Ensure the browser is not maximized
3. Shrink the browser window width to roughly half-size, then slowly widen the browser window while observing the chart elements.

Expected result: pie charts remain in centers of nuxeo-card elements while resizing browser.

Actual result: pie charts are aligned with left edges of nuxeo-card elements while resizing browser.