feat(api): prepare for aspirate in air gap

[sfoster1]

We should add a prepare-to-aspirate to the python protocol api air_gap command, where it can issue the command after we've moved to a known-dry position and before we actually dispense the airgap command. We know the position is dry and therefore it's safe to do a prepare.

However, to be able to unconditionally do a prepare, we also need to add a fix to the engine prepare command to no-op if the pipette is already prepared to aspirate. This is pretty important because if we've already aspirated some liquid, we really don't want to move back to the bottom position and dispense it all.

Useful testing protocol:

from opentrons.protocol_api import ProtocolContext

metadata = {"protocolName": "Test air gap prepare"}
requirements = {"apiLevel": "2.22", "robotType": "Flex"}


def run(protocol: ProtocolContext) -> None:
    plate = protocol.load_labware("biorad_384_wellplate_50ul", "A1")
    rack = protocol.load_labware("opentrons_flex_96_tiprack_50ul", "A2")
    pipette = protocol.load_instrument("flex_1channel_50", "left", tip_racks=[rack])

    pipette.pick_up_tip()
    pipette.aspirate(location=plate["A1"].bottom(z=2), volume=10)
    pipette.dispense(location=plate["A1"].top(), volume=10)
    pipette.blow_out(location=plate["A1"].top())
    pipette.air_gap(height=5, volume=10)

    pipette.dispense(location=plate["A2"].top(), volume=10)
    pipette.return_tip()

Closes EXEC-1391

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 25.82%. Comparing base (e1eac6f) to head (ace126d).
Report is 7 commits behind head on chore_release-8.4.0.

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[ddcc4]

since previously those protocols would neither analyze nor run.

Small nitpick: Until recently, protocols that were missing the prepare_to_aspirate() would analyze successfully (but fail when run), since analysis did not track whether the pipette was ready to aspirate.

[ddcc4]

Could you also update this error message to make it easier for users to figure out what's wrong? The problem we ran into last time was due to a push out, not a blow out.

[SyntaxColoring]

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[SyntaxColoring]

_AIR_GAP_TRACKING_ADDED_IN is 2.22 but we're about to release 2.23. Does this not need another api_version gate, or is it harmless enough that we're not worrying about it?