[FAB-12215]WYFA:Remove chainId in tx proposal request

A sample application in Write Your First Application has an
unnecessary parameter “chainId” in a transaction proposal request.
Since a channel name is included in a channel object, it is not
required in a request.

This CR removes the parameter ”chainId” from the document.

FAB-12215 #done

Change-Id: I99525f4b207002b8c58eba9df62a8f1c9fd1e5b0
Signed-off-by: Yuki Kondo <yuki.kondo@hal.hitachi.com>

Author: yuki-kon

docs/source/write_first_app.rst

@@ -390,7 +390,6 @@ code block where we construct our invocation:
     chaincodeId: 'fabcar',
     fcn: '',
     args: [''],
-    chainId: 'mychannel',
     txId: tx_id
   };
 
@@ -406,7 +405,6 @@ as the identifying key here. Edit this code block to look like this:
     chaincodeId: 'fabcar',
     fcn: 'createCar',
     args: ['CAR10', 'Chevy', 'Volt', 'Red', 'Nick'],
-    chainId: 'mychannel',
     txId: tx_id
   };
 
@@ -475,7 +473,6 @@ to ``changeCarOwner`` and input the arguments like this:
     chaincodeId: 'fabcar',
     fcn: 'changeCarOwner',
     args: ['CAR10', 'Dave'],
-    chainId: 'mychannel',
     txId: tx_id
   };