fix(regression): use built-in json variant + seed filters for log-filtering cases

The logs_filter_baseline/ottl/jq cases crashed on every replicate because
the templated_json lading variant requires an external template file
(/etc/lading/templated_json.yaml) that the SMP execution path does not
deliver to the lading container, so lading exited non-zero at startup.

Switch all three cases to lading's built-in `json` variant (no external
file) and filter on the built-in `seed` field (~50% selectivity) using
each engine's idiom: regex "seed":\d*[02468], / OTTL attributes["seed"]
< 32768 / jq select(.seed < 32768). Each case now processes the identical
stream and keeps ~half, keeping the per-engine CPU comparison fair.

Also removes the logs_filter_diag_apache crash-isolation case, which
confirmed the crash was specific to the templated_json path.

Author: rhy988

test/regression/cases/logs_filter_baseline/datadog-agent/conf.d/logs.d/conf.yaml

@@ -6,4 +6,4 @@ logs:
     log_processing_rules:
       - type: include_at_match
         name: baseline_only
-        pattern: '"name":"baseline"'
+        pattern: '"seed":\d*[02468],'

test/regression/cases/logs_filter_baseline/lading/lading.yaml

@@ -9,9 +9,7 @@ generator:
         maximum_bytes_per_log: 50MiB
         total_rotations: 5
         max_depth: 0
-        variant:
-          templated_json:
-            template_path: "/etc/lading/templated_json.yaml"
+        variant: json
         maximum_prebuild_cache_size_bytes: 300MiB
         mount_point: /smp-shared
 

test/regression/cases/logs_filter_baseline/lading/templated_json.yaml

@@ -6,4 +6,4 @@ logs:
     log_processing_rules:
       - type: include_at_jq_match
         name: jq_only
-        pattern: select(.name == "jq")
+        pattern: select(.seed < 32768)

test/regression/cases/logs_filter_diag_apache/datadog-agent/conf.d/logs.d/conf.yaml

@@ -9,9 +9,7 @@ generator:
         maximum_bytes_per_log: 50MiB
         total_rotations: 5
         max_depth: 0
-        variant:
-          templated_json:
-            template_path: "/etc/lading/templated_json.yaml"
+        variant: json
         maximum_prebuild_cache_size_bytes: 300MiB
         mount_point: /smp-shared