Bump Submodules/AMReX from 779df09 to 823ec7f

Bumps [Submodules/AMReX](https://github.com/AMReX-Codes/amrex) from `779df09` to `823ec7f`.
- [Release notes](https://github.com/AMReX-Codes/amrex/releases)
- [Commits](AMReX-Codes/amrex@779df09...823ec7f)

---
updated-dependencies:
- dependency-name: Submodules/AMReX
  dependency-type: direct:production
...

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Author: dependabot[bot]