[flake]: TestLightningTerminal/custom_channels_liquidity_group

[jtobin]

This test was observed failing in CI on #1863. (log).

--- FAIL: TestLightningTerminal (729.46s)
    --- PASS: TestLightningTerminal/custom_channels (119.65s)
    --- PASS: TestLightningTerminal/custom_channels_backward_compatibility (61.51s)
    --- PASS: TestLightningTerminal/custom_channels_large (67.55s)
    --- PASS: TestLightningTerminal/custom_channels_grouped_asset (115.68s)
    --- PASS: TestLightningTerminal/custom_channels_group_tranches_force_close (49.10s)
    --- PASS: TestLightningTerminal/custom_channels_group_tranches_htlc_force_close (56.31s)
    --- PASS: TestLightningTerminal/custom_channels_force_close (24.77s)
    --- PASS: TestLightningTerminal/custom_channels_breach (24.20s)
    --- PASS: TestLightningTerminal/custom_channels_liquidity (63.41s)
    assets_test.go:2924: Htlc event receive timeout
    assets_test.go:2924: Htlc event receive timeout
    --- FAIL: TestLightningTerminal/custom_channels_liquidity_group (147.27s)

        	Error:      	Received unexpected error:
        	            	expected 4 HTLCs, got 0, [..]