rpk: display float values as float in cluster config get

In 610e3ad we introduced a fix for redpanda-data#6070, to avoid
printing large numbers with scientific notation, we
treated all numbers as integers.

Now, the API uses float values and they are being
rounded, this change introduce a mod check to
determine whether the number is an integer or a
float.

(cherry picked from commit b7a57ed)

src/go/rpk/pkg/cli/cluster/config/get.go

@@ -11,6 +11,7 @@ package config
 
 import (
 	"fmt"
+	"math"
 
 	"github.com/redpanda-data/redpanda/src/go/rpk/pkg/adminapi"
 	"github.com/redpanda-data/redpanda/src/go/rpk/pkg/config"
@@ -48,10 +49,14 @@ output, use the 'edit' and 'export' commands respectively.`,
 			} else {
 				// currentConfig is the result of json.Unmarshal into a
 				// map[string]interface{}. Due to json rules, all numbers
-				// are float64. We do not want to print floats, especially
-				// for large numbers.
+				// are float64. We do not want to print floats for large
+				// numbers.
 				if f64, ok := val.(float64); ok {
-					val = int64(f64)
+					if math.Mod(f64, 1.0) == 0 {
+						val = int64(f64)
+					} else {
+						val = f64
+					}
 				}
 				// Intentionally bare output, so that the output can be readily
 				// consumed in a script.

tests/rptest/tests/cluster_config_test.py

@@ -1050,7 +1050,8 @@ class Example(NamedTuple):
             Example("kafka_qdc_enable", "true", True),
             Example("append_chunk_size", "32768", 32768),
             Example("superusers", "['bob','alice']", ["bob", "alice"]),
-            Example("storage_min_free_bytes", "1234567890", 1234567890)
+            Example("storage_min_free_bytes", "1234567890", 1234567890),
+            Example("kafka_memory_share_for_fetch", "0.6", 0.6)
         ]
 
         def yamlize(input) -> str: