Fix cat allocation YAML test (#126003)

This test failed when the `disk.indices.forecast` value was a decimal number.
We adjust the regex to allow decimal values and for consistency we also allow negative values.

Fixes #125711
Fixes #125848
Fixes #125661

Author: nielsbauman

muted-tests.yml

@@ -344,18 +344,12 @@ tests:
 - class: org.elasticsearch.xpack.ilm.actions.SearchableSnapshotActionIT
   method: testSearchableSnapshotsInHotPhasePinnedToHotNodes
   issue: https://github.com/elastic/elasticsearch/issues/125683
-- class: org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT
-  method: test {p0=cat.allocation/10_basic/Node forecasts}
-  issue: https://github.com/elastic/elasticsearch/issues/125711
 - class: org.elasticsearch.xpack.migrate.action.ReindexDataStreamTransportActionIT
   method: testAlreadyUpToDateDataStream
   issue: https://github.com/elastic/elasticsearch/issues/125727
 - class: org.elasticsearch.index.engine.ThreadPoolMergeSchedulerStressTestIT
   method: testMergingFallsBehindAndThenCatchesUp
   issue: https://github.com/elastic/elasticsearch/issues/125744
-- class: org.elasticsearch.test.rest.ClientYamlTestSuiteIT
-  method: test {yaml=cat.allocation/10_basic/Node forecasts}
-  issue: https://github.com/elastic/elasticsearch/issues/125661
 - class: org.elasticsearch.xpack.esql.spatial.SpatialExtentAggregationNoLicenseIT
   method: testStExtentAggregationWithPoints
   issue: https://github.com/elastic/elasticsearch/issues/125735
@@ -380,9 +374,6 @@ tests:
 - class: org.elasticsearch.multiproject.test.CoreWithMultipleProjectsClientYamlTestSuiteIT
   method: test {yaml=search.vectors/41_knn_search_bbq_hnsw/Test index configured rescore vector score consistency}
   issue: https://github.com/elastic/elasticsearch/issues/125902
-- class: org.elasticsearch.smoketest.SmokeTestMultiNodeClientYamlTestSuiteIT
-  method: test {yaml=cat.allocation/10_basic/Node forecasts}
-  issue: https://github.com/elastic/elasticsearch/issues/125848
 - class: org.elasticsearch.xpack.test.rest.XPackRestIT
   method: test {p0=ml/start_data_frame_analytics/Test start given dest index is not empty}
   issue: https://github.com/elastic/elasticsearch/issues/125909

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/cat.allocation/10_basic.yml

@@ -295,7 +295,7 @@
           ( [-\w.]+                \s+
             [-\w.]+                \s+
             [-\w.]+                \s+
-            [\w]+
+            [-\w.]+
             \n
           )+
         $/