NetworkPkg: Restore TPL Before Return

[os-d]

Description

This patch fixes a few instances of error cases in NetworkPkg returning after a RaiseTpl call without restoring the TPL first.

• [ ] Breaking change?
  • Breaking change - Does this PR cause a break in build or boot behavior?
  • Examples: Does it add a new library class or move a module to a different repo.
• [ ] Impacts security?
  • Security - Does this PR have a direct security impact?
  • Examples: Crypto algorithm change or buffer overflow fix.
• [ ] Includes tests?
  • Tests - Does this PR include any explicit test code?
  • Examples: Unit tests or integration tests.

How This Was Tested

Code review.

Integration Instructions

N/A.