remove some array and list allocations (open-telemetry#6133)

Author: SimonCropp

src/OpenTelemetry/Metrics/View/ExplicitBucketHistogramConfiguration.cs

@@ -25,7 +25,7 @@ public class ExplicitBucketHistogramConfiguration : HistogramConfiguration
     /// </remarks>
     public double[]? Boundaries
     {
-        get => this.CopiedBoundaries != null ? this.CopiedBoundaries.AsSpan().ToArray() : null;
+        get => this.CopiedBoundaries?.ToArray();
 
         set
         {
@@ -36,7 +36,7 @@ public double[]? Boundaries
                     throw new ArgumentException($"Histogram boundaries are invalid. Histogram boundaries must be in ascending order with distinct values.", nameof(value));
                 }
 
-                this.CopiedBoundaries = value.AsSpan().ToArray();
+                this.CopiedBoundaries = value.ToArray();
             }
             else
             {

src/OpenTelemetry/Metrics/View/MetricStreamConfiguration.cs

@@ -71,8 +71,8 @@ public string? Name
     /// </remarks>
     public string[]? TagKeys
     {
-        get => this.CopiedTagKeys != null ? this.CopiedTagKeys.AsSpan().ToArray() : null;
-        set => this.CopiedTagKeys = value != null ? value.AsSpan().ToArray() : null;
+        get => this.CopiedTagKeys?.ToArray();
+        set => this.CopiedTagKeys = value?.ToArray();
     }
 
     /// <summary>

src/Shared/Options/DelegatingOptionsFactory.cs

@@ -64,9 +64,9 @@ public DelegatingOptionsFactory(
 
         this.optionsFactoryFunc = optionsFactoryFunc!;
         this.configuration = configuration!;
-        _setups = setups as IConfigureOptions<TOptions>[] ?? new List<IConfigureOptions<TOptions>>(setups).ToArray();
-        _postConfigures = postConfigures as IPostConfigureOptions<TOptions>[] ?? new List<IPostConfigureOptions<TOptions>>(postConfigures).ToArray();
-        _validations = validations as IValidateOptions<TOptions>[] ?? new List<IValidateOptions<TOptions>>(validations).ToArray();
+        _setups = setups as IConfigureOptions<TOptions>[] ?? setups.ToArray();
+        _postConfigures = postConfigures as IPostConfigureOptions<TOptions>[] ?? postConfigures.ToArray();
+        _validations = validations as IValidateOptions<TOptions>[] ?? validations.ToArray();
     }
 
     /// <summary>