SecurityPkg/HashInstanceLibSha1: Added Allocation check for codeql (#163)

## Description

A small change to check if we're able to successfully allocate. This
allows us to pass CodeQL checks.

- [ ] 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

Tested to make sure physical platforms could boot. Also confirmed codeql
tests pass as well.

## Integration Instructions

N/A

SecurityPkg/Library/HashInstanceLibSha1/HashInstanceLibSha1.c

@@ -56,7 +56,13 @@ Sha1HashInit (
 
   CtxSize = Sha1GetContextSize ();
   Sha1Ctx = AllocatePool (CtxSize);
-  ASSERT (Sha1Ctx != NULL);
+  // MU_CHANGE [BEGIN] - CodeQL change
+  if (Sha1Ctx == NULL) {
+    ASSERT (Sha1Ctx != NULL);
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  // MU_CHANGE [END] - CodeQL change
 
   Sha1Init (Sha1Ctx);