remove map transitions
remove map transitions

Previously there were 200ms transitions that were used during the rendering calls within `maybeUpdateDemesAndTransmissions`. This caused issues with arcs (pie charts) when we tried to change the path attr during a transition. Removing these is a very slight regression in appearance but a major increase in speed. Furthermore, since 4a1d8231770989a5e70753224cde746dbc97cec0 causes a removal & recreation of DOM elements on a color-by change (not an update), these transitions are only ever applied by visibility changes. Especially in animations this is unnecessary complexity & cost.
nextstrain/auspice,nextstrain/auspice,nextstrain/auspice