Headers already sent Warning if Yes mode or Debug mode activated

[yorkshire-pudding]

This is due to the switch to using bee_instant_message() for notifying about Yes mode and Debug mode (oops). It still makes sense to do before the command, but it should now be done after bootstrap.

Steps to reproduce

1. Run a command that uses bootstrap with debug mode or yes mode enabled (e.g. bee projects -d)

Expected results
Command runs with the notification about Yes mode or debug mode then the command output

Actual results

 ℹ  'Yes' mode enabled.

 ⚠️ Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent
in backdrop_environment_initialize() (line 749 of /app/docroot/core/includes/bootstrap.inc).


 ⚠️ Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent
in backdrop_environment_initialize() (line 750 of /app/docroot/core/includes/bootstrap.inc).


 ⚠️ Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent
in backdrop_environment_initialize() (line 751 of /app/docroot/core/includes/bootstrap.inc).


 ⚠️ Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent
in backdrop_environment_initialize() (line 754 of /app/docroot/core/includes/bootstrap.inc).


 ⚠️ Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent
in backdrop_environment_initialize() (line 756 of /app/docroot/core/includes/bootstrap.inc).


 ⚠️ Warning: session_name(): Session name cannot be changed after headers have already been sent
in backdrop_settings_initialize() (line 1000 of /app/docroot/core/includes/bootstrap.inc).

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