merge: bring the CI fixes forward from phase6-statsd

Three conflicts, all resolved by keeping this branch's rewrite and
re-applying the incoming change onto it:

- 09-data-collection-reference.md: phase-7 rewrote both attribute tables,
  so the incoming table would have reverted them. Kept phase-7's and
  re-applied the two "XRPL epoch" spellings.
- integration-test.sh: phase-7 moved these checks from StatsD to OTel and
  no longer defines check_statsd_metric, so only this side compiles.
- TelemetryConfig.cpp: the incoming side carried networkTypeFromId(), which
  this branch already has. Kept one definition and took the incoming
  doc wording, which the auto-merged body below it already matches.

.github/scripts/strategy-matrix/linux.json

@@ -74,7 +74,7 @@
         "extra_cmake_args": "-Dvalidator_keys=ON",
         "package": {
           "type": "deb",
-          "image": "ghcr.io/xrplf/xrpld/packaging-debian:sha-b6a8995"
+          "image": "ghcr.io/xrplf/xrpld/packaging-debian:sha-49cdc10"
         }
       }
     ],
@@ -88,7 +88,7 @@
         "extra_cmake_args": "-Dvalidator_keys=ON",
         "package": {
           "type": "rpm",
-          "image": "ghcr.io/xrplf/xrpld/packaging-rhel:sha-b6a8995"
+          "image": "ghcr.io/xrplf/xrpld/packaging-rhel:sha-49cdc10"
         }
       }
     ]