Bump the python group in /tests with 2 updates (#5263)

Bumps the python group in /tests with 2 updates: [flaky](https://github.com/box/flaky) and [protobuf](https://github.com/protocolbuffers/protobuf).


Updates `flaky` from 3.8.0 to 3.8.1
- [Release notes](https://github.com/box/flaky/releases)
- [Changelog](https://github.com/box/flaky/blob/master/HISTORY.rst)
- [Commits](box/flaky@v3.8.0...v3.8.1)

Updates `protobuf` from 4.25.3 to 5.26.0
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](protocolbuffers/protobuf@v4.25.3...v5.26.0)

---
updated-dependencies:
- dependency-name: flaky
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: python
- dependency-name: protobuf
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: python
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

tests/requirements.txt

@@ -207,9 +207,9 @@ cryptography==42.0.5 \
     # via
     #   -r requirements.txt
     #   pyopenssl
-flaky==3.8.0 \
-    --hash=sha256:06152dc0582c18e2cc3d241feece008c074b17e1292658cb39ff8464ae19bd89 \
-    --hash=sha256:3b4b9f5c15829c919c8e05b15582fa1c9c7f20a303581dd5d0bc56a66441389c
+flaky==3.8.1 \
+    --hash=sha256:194ccf4f0d3a22b2de7130f4b62e45e977ac1b5ccad74d4d48f3005dcc38815e \
+    --hash=sha256:47204a81ec905f3d5acfbd61daeabcada8f9d4031616d9bcb0618461729699f5
     # via -r requirements.txt
 forcediphttpsadapter==1.1.0 \
     --hash=sha256:0d224cf6e8e50eb788c9f5994a7afa6d389bac6dbe540b7dfd77a32590ad0153 \
@@ -453,18 +453,18 @@ pluggy==1.4.0 \
     # via
     #   -r requirements.txt
     #   pytest
-protobuf==4.25.3 \
-    --hash=sha256:19b270aeaa0099f16d3ca02628546b8baefe2955bbe23224aaf856134eccf1e4 \
-    --hash=sha256:209ba4cc916bab46f64e56b85b090607a676f66b473e6b762e6f1d9d591eb2e8 \
-    --hash=sha256:25b5d0b42fd000320bd7830b349e3b696435f3b329810427a6bcce6a5492cc5c \
-    --hash=sha256:7c8daa26095f82482307bc717364e7c13f4f1c99659be82890dcfc215194554d \
-    --hash=sha256:c053062984e61144385022e53678fbded7aea14ebb3e0305ae3592fb219ccfa4 \
-    --hash=sha256:d4198877797a83cbfe9bffa3803602bbe1625dc30d8a097365dbc762e5790faa \
-    --hash=sha256:e3c97a1555fd6388f857770ff8b9703083de6bf1f9274a002a332d65fbb56c8c \
-    --hash=sha256:e7cb0ae90dd83727f0c0718634ed56837bfeeee29a5f82a7514c03ee1364c019 \
-    --hash=sha256:f0700d54bcf45424477e46a9f0944155b46fb0639d69728739c0e47bab83f2b9 \
-    --hash=sha256:f1279ab38ecbfae7e456a108c5c0681e4956d5b1090027c1de0f934dfdb4b35c \
-    --hash=sha256:f4f118245c4a087776e0a8408be33cf09f6c547442c00395fbfb116fac2f8ac2
+protobuf==5.26.0 \
+    --hash=sha256:2c334550e1cb4efac5c8a3987384bf13a4334abaf5ab59e40479e7b70ecd6b19 \
+    --hash=sha256:6ee9d1aa02f951c5ce10bf8c6cfb7604133773038e33f913183c8b5201350600 \
+    --hash=sha256:7e47c57303466c867374a17b2b5e99c5a7c8b72a94118e2f28efb599f19b4069 \
+    --hash=sha256:82f5870d74c99addfe4152777bdf8168244b9cf0ac65f8eccf045ddfa9d80d9b \
+    --hash=sha256:8eef61a90631c21b06b4f492a27e199a269827f046de3bb68b61aa84fcf50905 \
+    --hash=sha256:a49b6c5359bf34fb7bf965bf21abfab4476e4527d822ab5289ee3bf73f291159 \
+    --hash=sha256:ca825f4eecb8c342d2ec581e6a5ad1ad1a47bededaecd768e0d3451ae4aaac2b \
+    --hash=sha256:dfd29f6eb34107dccf289a93d44fb6b131e68888d090b784b691775ac84e8213 \
+    --hash=sha256:e184175276edc222e2d5e314a72521e10049938a9a4961fe4bea9b25d073c03f \
+    --hash=sha256:efd4f5894c50bd76cbcfdd668cd941021333861ed0f441c78a83d8254a01cc9f \
+    --hash=sha256:f9ecc8eb6f18037e0cbf43256db0325d4723f429bca7ef5cd358b7c29d65f628
     # via
     #   -r requirements.txt
     #   grpcio-tools