[addons] fix addon install if not present before

[AlwinEsch]

On last changes comes the problem that a addon install who was not present
before has not worked.

This comes from a try to disable a addon who is not present and brought a
false.

With them becomes before checked that a addon is present, otherwise is this
step ignored.

Related to #12473 (review)

Description

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the Code guidelines of this project
• My change requires a change to the documentation, either Doxygen or wiki
• I have updated the documentation accordingly
• I have read the CONTRIBUTING document
• I have added tests to cover my change
• All new and existing tests passed

[AlwinEsch]

@tamland is this fix OK for you, that we bring it in asap?

[tamland]

This check needs to be move inside UnloadAddon (I.e it should return true if the addon isn't installed). Otherwise there are race conditions

[AlwinEsch]

Is changed.

Think to replace the CAddonMgr::GetInstance() with CServiceBroker::GetAddonMgr() on all places on another request

[stefansaraev]

works for me. thanks @AlwinEsch @tamland

[AlwinEsch]

Install test has worked, but there seems still a fault with start of a new installed addon.

If I have installed YouTube and start it are the strings from them not visible. Also brings it a Python error after select of a field.

If Kodi is restarted does it work, there seems the loading of new installed addon not work!

[stefansaraev]

yep same behaviour here. I thought it was unrelated but indeed completely reverting #12473 makes those strings work again...

[AlwinEsch]

Have added a second commit who fix the fault with not usable addon after install.

The fault itself was coming after the change of the function value AddonPtr& addon to const std::string& addonId on the LoadAddon (old ReloadAddon).

If all commits are reverted and only this with change to std::string is done, comes the fault.

The function has changed the addon class on CAddonInstaller.

[AlwinEsch]

Is changed to use GetAddon

[tamland]

Thanks! Merge when ready