SetupBrowserDxe: Initialize the variable 'BrowserStorage' (#346)

# Preface

Fix potential error from CodeQL fixes ([commit
df0aadd](df0aadd))
that resulted in an uninitialized variable attempting to be used.

## Description

Initialize the variable 'BrowserStorage' to avoid it's used but
uninitialized when the logic route through an if statement.

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- [ ] Impacts functionality?
- **Functionality** - Does the change ultimately impact how firmware
functions?
- Examples: Add a new library, publish a new PPI, update an algorithm,
...
- [ ] Impacts security?
- **Security** - Does the change have a direct security impact on an
application,
    flow, or firmware?
  - Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
- [ ] Breaking change?
- **Breaking change** - Will anyone consuming this change experience a
break
    in build or boot behavior?
- Examples: Add a new library class, move a module to a different repo,
call
    a function in a new library class in a pre-existing module, ...
- [ ] Includes tests?
  - **Tests** - Does the change include any explicit test code?
  - Examples: Unit tests, integration tests, robot tests, ...
- [ ] Includes documentation?
- **Documentation** - Does the change contain explicit documentation
additions
    outside direct code modifications (and comments)?
- Examples: Update readme file, add feature readme file, link to
documentation
    on an a separate Web page, ...

## How This Was Tested

Built several times with the change locally, and the system boots.

## Integration Instructions

N/A

MdeModulePkg/Universal/SetupBrowserDxe/IfrParse.c

@@ -438,8 +438,9 @@ CreateStorage (
   EFI_GUID         *StorageGuid;
   CHAR8            *StorageName;
 
-  UnicodeString = NULL;
-  StorageName   = NULL;
+  UnicodeString  = NULL;
+  StorageName    = NULL;
+  BrowserStorage = NULL; // MU_CHANGE - Initialize variable that might not be updated due to error checking
   switch (StorageType) {
     case EFI_HII_VARSTORE_BUFFER:
       StorageGuid = (EFI_GUID *)(CHAR8 *)&((EFI_IFR_VARSTORE *)OpCodeData)->Guid;
@@ -534,11 +535,11 @@ CreateStorage (
     FreePool (BrowserStorage);
   }
 
-  if (Storage->ConfigRequest != NULL) {
-    FreePool (Storage->ConfigRequest);
-  }
-
   if (Storage != NULL) {
+    if (Storage->ConfigRequest != NULL) {
+      FreePool (Storage->ConfigRequest);
+    }
+
     FreePool (Storage);
   }