Fix contact-sensor-app example binary name (#35436)

* Update README.md

Fix contact-sensor-app example binary name

* Update README.md
diff --git a/examples/contact-sensor-app/linux/README.md b/examples/contact-sensor-app/linux/README.md
index f99162f..e71ea89 100644
--- a/examples/contact-sensor-app/linux/README.md
+++ b/examples/contact-sensor-app/linux/README.md
@@ -69,11 +69,6 @@
 
 ## Running the Complete Example on Raspberry Pi 4
 
-> If you want to test Echo protocol, please enable Echo handler
->
->     gn gen out/debug --args='chip_app_use_echo=true'
->     ninja -C out/debug
-
 -   Prerequisites
 
     1. A Raspberry Pi 4 board
@@ -112,7 +107,7 @@
                   $ cd ~/connectedhomeip/examples/contact-sensor-app/linux
                   $ sudo out/debug/chip-contact-sensor-app --ble-device [bluetooth device number]
                   # In this example, the device we want to use is hci1
-                  $ sudo out/debug/chip-contact-sensor-app --ble-device 1
+                  $ sudo out/debug/contact-sensor-app --ble-device 1
 
         -   Test the device using ChipDeviceController on your laptop /
             workstation etc.