[BUG] FlexForm settings are not read in controller classes

[beatrycze-volk]

Description

The settings array should contain settings from FlexForm but instead it contains only configuration from TypoScript.

Reproduction

See: #1298

Expected Behavior

Settings from FlexForms should be available inside the controller classes.

Screenshots and Examples

See: #1298

Environment

See: #1298

Additional Context

Currently two counter measures are introduced but they only mask the error instead of fix it:

• [BUGFIX] Check if array is not null before checking for the existence of the key #1322
• [MAINTENANCE] Sanitize settings from FlexForm #1324

Probably bug was introduced during the update to TYPO3 11.x.

[beatrycze-volk]

After additional research we have found that FlexForms are read but the integration of the plugins happens mostly by including TypoScript objects:
<f:cObject typoscriptObjectPath="plugin.tx_dlf_pageview" />

Because of that the FlexForm settings are read and then overwritten by TS settings.