niv motoko-base: update 8fd23fa7 -> a3dd04eb

## Changelog for motoko-base:
Branch: next-moc
Commits: [dfinity/motoko-base@8fd23fa7...a3dd04eb](dfinity/motoko-base@8fd23fa...a3dd04e)

* [`cee15564`](dfinity/motoko-base@cee1556) feat: add `isReplicated` to `ExperimentalInternetComputer` ([dfinity/motoko-base⁠#694](https://togithub.com/dfinity/motoko-base/issues/694))
* [`c9a08167`](dfinity/motoko-base@c9a0816) feat: add `Error.isRetryPossible`, a predicate for non-fatal messaging errors ([dfinity/motoko-base⁠#692](https://togithub.com/dfinity/motoko-base/issues/692))
* [`6246b654`](dfinity/motoko-base@6246b65) feat: make `replyDeadline` an optional return type ([dfinity/motoko-base⁠#693](https://togithub.com/dfinity/motoko-base/issues/693))
* [`1a381b99`](dfinity/motoko-base@1a381b9) Motoko 0.14.3
* [`756855bc`](dfinity/motoko-base@756855b) chore: amend the 0.14.3 changelog ([dfinity/motoko-base⁠#697](https://togithub.com/dfinity/motoko-base/issues/697))

Author: dfinity-bot

nix/sources.json

@@ -75,10 +75,10 @@
         "homepage": "",
         "owner": "dfinity",
         "repo": "motoko-base",
-        "rev": "8fd23fa749290e254a6c411659837b3eed905611",
-        "sha256": "1llzpkc3pza5hc0vh4rwais6hf1s554jck12vvv755rgsbn1ypf1",
+        "rev": "a3dd04ebd3e81993e20c47bff577f58abca9d335",
+        "sha256": "0lsnyn49sgp75w5wrdj76l707jpxl0iycpvafdwb7ljv1x9glba8",
         "type": "tarball",
-        "url": "https://github.com/dfinity/motoko-base/archive/8fd23fa749290e254a6c411659837b3eed905611.tar.gz",
+        "url": "https://github.com/dfinity/motoko-base/archive/a3dd04ebd3e81993e20c47bff577f58abca9d335.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "motoko-matchers": {