[DOCS] Add experimental label to TSDB mapping params and settings (#79647)

Adds an `experimental` annotation to the following:

* `time_series_metric` mapping parameter
* `time_series_dimension` mapping parameter
* `index.mapping.dimension_fields.limit` index setting
*  `time_series_dimension` and `time_series_metric` properties in the field caps API response

docs/reference/index-modules.asciidoc

@@ -331,6 +331,7 @@ pipeline attempts to change the `_index` field, the indexing request will fail.
 
 [[index-mapping-dimension-fields-limit]]
 `index.mapping.dimension_fields.limit`::
+experimental:[] 
 For internal use by Elastic only. Maximum number of time series dimensions for
 the index. Defaults to `16`.
 +

docs/reference/mapping/types/keyword.asciidoc

@@ -149,6 +149,7 @@ The following parameters are accepted by `keyword` fields:
 
 // tag::dimension[]
 `time_series_dimension`::
+experimental:[]
 (Optional, Boolean) For internal use by Elastic only. Marks the field as a time
 series dimension. Defaults to `false`.
 +

docs/reference/mapping/types/numeric.asciidoc

@@ -179,6 +179,7 @@ A numeric field can't be both a time series dimension and a time series metric.
 
 // tag::time_series_metric[]
 `time_series_metric`::
+experimental:[]
 (Optional, string) For internal use by Elastic only. Marks the field as a time
 series metric. The value is the metric type. Defaults to `null` (Not a time
 series metric).

docs/reference/search/field-caps.asciidoc

@@ -112,9 +112,11 @@ field types are all described as the `keyword` type family.
   Whether this field can be aggregated on all indices.
 
 `time_series_dimension`::
+  experimental:[]
   Whether this field is used as a time series dimension.
 
 `time_series_metric`::
+  experimental:[]
   Contains metric type if this fields is used as a time series metrics, absent if the field is not used as metric.
 
 `indices`::
@@ -130,10 +132,12 @@ field types are all described as the `keyword` type family.
   indices have the same definition for the field.
 
 `non_dimension_indices`::
+  experimental:[]
   If this list is present in response then some indices have the field marked as a dimension and other indices, the
   ones in this list, do not.
 
 `metric_conflicts_indices`::
+  experimental:[]
   The list of indices where this field is present if these indices don't have the same `time_series_metric` value for
   this field.