Decompose OptionRowLHN avatar/delegate logic into a separate component

[JS00001]

Explanation of Change
Extracts the avatar rendering and delegate-avatar substitution logic into a child component (OptionRowAvatar). The four delegate-related derivations (delegateAccountID, skipDelegate, icons, delegateTooltipAccountID) and the usePersonalDetails read move out of the parent row. useCurrentUserPersonalDetails stays in the parent (still consumed for status timezone). The null-render short-circuit when !optionItem.icons?.length || !firstIcon is preserved inside the child. React.memo(OptionRowLHN) is preserved.

Measured impact
ManualNavigateToInboxTab: 626ms → 596ms (~4.8%)

PR: #89087

Issue Owner

Current Issue Owner: @BartekObudzinski

[melvin-bot]

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