Fallback schedule with all 0 values instead of best effort to reach impossible target

[ArdJonker]

Context: Request a schedule with current SoC: 36% (of 59 kWh) Target (calendar item) 80% within two hours (unreachable).

Result: Fallback schedule with all 0 values.

Expected result: Schedule that starts charging with maximum power to get as close as possible to the unreachable target.

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Schedule id: f2bebb17-b17b-4605-aaba-1d1c02aea8cf

Trigger message: 2024-03-05 15:12:59.717814 INFO flexmeasures-client: Trigger_schedule on url 'https://seita.energy/api/v3_0/sensors/99/schedules/trigger', with message: '{'start': '2024-03-05T15:15:00+01:00', 'flex-model': {'soc-at-start': 21.24, 'soc-unit': 'kWh', 'soc-min': 10.62, 'soc-max': 59, 'soc-minima': [{'value': 47.2, 'datetime': '2024-03-05T16:00:00+01:00'}], 'soc-maxima': [{'value': 47.2, 'datetime': '2024-03-05T15:15:00+01:00'}, {'value': 47.2, 'datetime': '2024-03-05T15:20:00+01:00'}, {'value': 47.2, 'datetime': '2024-03-05T15:25:00+01:00'}, {'value': 47.2, 'datetime': '2024-03-05T15:30:00+01:00'}, {'value': 47.2, 'datetime': '2024-03-05T15:35:00+01:00'}, {'value': 47.2, 'datetime': '2024-03-05T15:40:00+01:00'}, {'value': 47.2, 'datetime': '2024-03-05T15:45:00+01:00'}, {'value': 47.2, 'datetime': '2024-03-05T15:50:00+01:00'}, {'value': 47.2, 'datetime': '2024-03-05T15:55:00+01:00'}], 'roundtrip-efficiency': 0.85, 'power-capacity': '5750W'}, 'flex-context': {'consumption-price-sensor': 90, 'production-price-sensor': 91}}'.