Multi inverter fixes, change to default for plan_forecast_hours

What's Changed

Potentially breaking change

Forecast plan hours was meant to default in 24 hours in non-expert mode but due to a bug it defaulted to 48. This has now been changed, however if you want to go back to 48 hours then you will need to enable expert mode and change plan_forecast_hours to 48.

• Forecast plan hours default should be 24 hours, but was 48 due to bug by @springfall2008 in #1810

Bug fixes

• Attempt to fix unstable plan by @springfall2008 in #1799
• Fix typo in change to fix unstable plan by @springfall2008 in #1800

Changes to try to ensure that the current charge window is kept once it has started, this was previously not working on multi-inverter systems:

• Fixes when battery level is below SOC to prevent spurious freeze by @springfall2008 in #1803
• Prevent freeze/hold charge if all inverters can't do it by @springfall2008 in #1806
• Bugs around freeze charging and low SOC on multi inverters by @springfall2008 in #1808

Fixed some bugs around multi-inverter and charge freeze and charge hold where the SOC of the different inverters was out of balance leading to strange behaviour

• Fix toggling on scheduled_discharge_enable dummy sensor in GE mode by @springfall2008 in #1804

Fixed some spurious toggling of a HA entity

Other

• Downgrade inverter type warning to info by @springfall2008 in #1805
• Unit tests updated by @springfall2008 in #1809

Full Changelog: v8.8.16...v8.8.17