fix(zero): fix update membership to make bulk tablet proposal instead of multiple small (#8090)

[all-seeing-code]

Converting the smaller tablet proposals into a single bulk call makes the execution faster. Else, this update becomes of the order of O(n^2), where n is the number of tablet updates.

(cherry picked from commit 695c6d7)

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[coveralls]

Coverage: 64.336% (-0.03%) from 64.366% when pulling 8c05356 on anurag/cp-propasal-membership into 8c72479 on main.

[skrdgraph]

Looks good!