Pass base::TimeDelta by value

[cdesouza-chromium]

For trivially copyable types like base::TimeDelta, we should avoid passing them as reference, as the cost is exactly the same as passing by value.

This change also turns many of the non-scoped constants into constexpr.

Resolves

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Test Plan:

[yrliou]

wallet++

[brave-builds]

Released in v1.72.63