tests: bluetooth: init: Remove duplicate prj_<x>.conf files

Remove duplicated prj.conf file.

prj_6, prj_7, prj_14 are identicall. Since prj_6.conf is unchanged,
keeping it.

prj_8, prj_9, prj_15 are identicall. Since prj_15.conf is
unchanged, keeping it.

Signed-off-by: Pavel Vasilyev <pavel.vasilyev@nordicsemi.no>

tests/bluetooth/init/prj_14.conf

@@ -1,5 +0,0 @@
-CONFIG_BT=y
-CONFIG_BT_PERIPHERAL=y
-CONFIG_BT_CENTRAL=y
-CONFIG_BT_SMP=y
-CONFIG_ZTEST=y

tests/bluetooth/init/prj_7.conf

@@ -1,5 +0,0 @@
-CONFIG_BT=y
-CONFIG_BT_PERIPHERAL=y
-CONFIG_BT_CENTRAL=y
-CONFIG_BT_SMP=y
-CONFIG_ZTEST=y

tests/bluetooth/init/prj_8.conf

@@ -1,6 +0,0 @@
-CONFIG_BT=y
-CONFIG_BT_PERIPHERAL=y
-CONFIG_BT_CENTRAL=y
-CONFIG_BT_SMP=y
-CONFIG_BT_SMP_SC_ONLY=y
-CONFIG_ZTEST=y

tests/bluetooth/init/prj_9.conf

@@ -1,6 +0,0 @@
-CONFIG_BT=y
-CONFIG_BT_PERIPHERAL=y
-CONFIG_BT_CENTRAL=y
-CONFIG_BT_SMP=y
-CONFIG_BT_SMP_SC_ONLY=y
-CONFIG_ZTEST=y

tests/bluetooth/init/testcase.yaml

@@ -22,9 +22,6 @@ tests:
   bluetooth.init.test_13:
     extra_args: CONF_FILE=prj_13.conf
     platform_allow: qemu_cortex_m3
-  bluetooth.init.test_14:
-    extra_args: CONF_FILE=prj_14.conf
-    platform_allow: qemu_cortex_m3
   bluetooth.init.test_15:
     extra_args: CONF_FILE=prj_15.conf
     platform_allow: qemu_cortex_m3
@@ -64,15 +61,6 @@ tests:
   bluetooth.init.test_6:
     extra_args: CONF_FILE=prj_6.conf
     platform_allow: qemu_cortex_m3
-  bluetooth.init.test_7:
-    extra_args: CONF_FILE=prj_7.conf
-    platform_allow: qemu_cortex_m3
-  bluetooth.init.test_8:
-    extra_args: CONF_FILE=prj_8.conf
-    platform_allow: qemu_cortex_m3
-  bluetooth.init.test_9:
-    extra_args: CONF_FILE=prj_9.conf
-    platform_allow: qemu_cortex_m3
   bluetooth.init.test_ctlr:
     extra_args: CONF_FILE=prj_ctlr.conf
     platform_allow: