estimateGas can return under 21000

[K-Ho]

Is your feature request related to a problem? Please describe.
Right now, estimateGas can return under 21000 if the "feeInGwei" is less than 21000 gwei. However, Metamask prevents sending transactions with a gasLimit of under 21000.

Describe the solution you'd like
A potential hack here is for estimateGas to return the Max(21000, estimateGas(tx))

Describe alternatives you've considered
Really, we need to look into alternatives, as it appears the downstream effects of this hack will be very numerous.

[smartcontracts]

it appears the downstream effects of this hack will be very numerous.

What sort of downstream effects have you observed?

[K-Ho]

To clarify: there are downstream effects of having estimateGas be “estimateFeeInGwei” - results in confusion around gasUsed being > than gasLimit, these metamask issues, issues with sending a tx with a gasLimit greater than the block gas limit.

[smartcontracts]

Closed by #695