fix: Isolate logic to expose js env variables sooner (#8202)

## **Description**
When creating a new terminal and trying to run any of the building
commands like `yarn setup` `yarn watch` `yarn start:android` and `yarn
start:ios`

It would give an error that the environment variables are not loaded

The problem was that we were checking if the variables were loaded
before they were actually loaded.

The solution is to load the variables as one of the first steps if they
exist.

## **Related issues**

Fixes:

## **Manual testing steps**

1. Go to this page...
2.
3.

## **Screenshots/Recordings**

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before and after of your change. -->

### **Before**

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### **After**

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## **Pre-merge author checklist**

- [ ] I’ve followed [MetaMask Coding
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is solved.
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## **Pre-merge reviewer checklist**

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in the ticket it closes and includes the necessary testing evidence such
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scripts/build.sh

@@ -132,19 +132,21 @@ remapFlaskEnvVariables() {
 	remapEnvVariable "MM_FLASK_MIXPANEL_TOKEN" "MM_MIXPANEL_TOKEN"
 }
 
-
-
-prebuild(){
-	# Import provider
-	yarn --ignore-engines build:static-logos
-
+loadJSEnv(){
 	# Load JS specific env variables
 	if [ "$PRE_RELEASE" = false ] ; then
 		if [ -e $JS_ENV_FILE ]
 		then
 			source $JS_ENV_FILE
 		fi
 	fi
+}
+
+
+prebuild(){
+	# Import provider
+	yarn --ignore-engines build:static-logos
+
   WATCHER_PORT=${WATCHER_PORT:-8081}
 }
 
@@ -541,7 +543,9 @@ checkAuthToken() {
 
 checkParameters "$@"
 
+
 printTitle
+loadJSEnv
 if [ "$MODE" == "releaseE2E" ] || [ "$MODE" == "QA" ] || [ "$MODE" == "QAE2E" ]; then
 	echo "DEBUG SENTRY PROPS"
 	checkAuthToken 'sentry.debug.properties'