fix: replace deprecated --id flag in stellar contract deploy (cross-contract-call example)

Author: kaankacar

docs/build/smart-contracts/example-contracts/cross-contract-call.mdx

@@ -261,13 +261,17 @@ If you have [`stellar-cli`] installed, you can invoke contract functions. Both c
 ```sh
 stellar contract deploy \
     --wasm target/wasm32v1-none/release/soroban_cross_contract_a_contract.wasm \
-    --id a
+    --alias cross_contract_a_example \
+    --source-account alice \
+    --network testnet
 ```
 
 ```sh
 stellar contract deploy \
     --wasm target/wasm32v1-none/release/soroban_cross_contract_b_contract.wasm \
-    --id b
+    --alias cross_contract_b_example \
+    --source-account alice \
+    --network testnet
 ```
 
 </TabItem>
@@ -276,13 +280,17 @@ stellar contract deploy \
 ```powershell
 stellar contract deploy `
     --wasm target/wasm32v1-none/release/soroban_cross_contract_a_contract.wasm `
-    --id a
+    --alias cross_contract_a_example `
+    --source-account alice `
+    --network testnet
 ```
 
 ```powershell
 stellar contract deploy `
     --wasm target/wasm32v1-none/release/soroban_cross_contract_b_contract.wasm `
-    --id b
+    --alias cross_contract_b_example `
+    --source-account alice `
+    --network testnet
 ```
 
 </TabItem>
@@ -295,10 +303,12 @@ Invoke Contract B's `add_with` function, passing in values for `x` and `y` (e.g.
 
 ```sh
 stellar contract invoke \
-    --id b \
+    --id cross_contract_b_example \
+    --source-account alice \
+    --network testnet \
     -- \
     add_with \
-    --contract a \
+    --contract cross_contract_a_example \
     --x 5 \
     --y 7
 ```
@@ -308,10 +318,12 @@ stellar contract invoke \
 
 ```powershell
 stellar contract invoke `
-    --id b `
+    --id cross_contract_b_example `
+    --source-account alice `
+    --network testnet `
     -- `
     add_with `
-    --contract a `
+    --contract cross_contract_a_example `
     --x 5 `
     --y 7
 ```