Revert "Replace system_ext container with system"

This reverts commit 6e1b274.

A system partition cannot have the aconfigs of other partitions.
Revive the system_ext container for system_ext aconfigs.

Bug: 385213580
Test: "adb shell aflags list" must not be changed.
Flag: EXEMPT refactor
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:1337a88d112b005f897b3745b5475cf7d4764db7)
Merged-In: I8f52d5f86e6ffaccd624846fbe1ba0a8fc842af6
Change-Id: I8f52d5f86e6ffaccd624846fbe1ba0a8fc842af6

Author: Justin Yun

aconfig/catalyst/accessibility.aconfig

@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "catalyst_accessibility_color_and_motion"

aconfig/catalyst/battery.aconfig

@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "catalyst_power_usage_summary_screen"

aconfig/catalyst/connected_devices.aconfig

@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "catalyst_bluetooth_switchbar_screen"

aconfig/catalyst/display.aconfig

@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "catalyst_display_settings_screen"

aconfig/catalyst/location.aconfig

@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "catalyst_location_settings"

aconfig/catalyst/lockscreen.aconfig

@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "catalyst_lockscreen_from_display_settings"

aconfig/catalyst/network_and_internet.aconfig

@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "catalyst_network_provider_and_internet_screen"

aconfig/catalyst/sound_screen.aconfig

@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
     name: "catalyst_sound_screen"

aconfig/catalyst/system.aconfig

@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
     name: "catalyst_language_setting"

aconfig/keyboard/settings_keyboard_layout_picker_features.aconfig

@@ -1,5 +1,5 @@
 package: "com.android.settings.keyboard"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "keyboard_layout_picker_activity_enabled"