Fix some friend access violations by allowing others access. (#8594)

Rename Friend attribute to Access attribute.
Updates submodule to v0.21.0.0 as well.

Content.Server/Fluids/Components/AbsorbentComponent.cs

@@ -7,7 +7,7 @@ namespace Content.Server.Fluids.Components;
 /// <summary>
 /// For entities that can clean up puddles
 /// </summary>
-[RegisterComponent, Friend(typeof(MoppingSystem))]
+[RegisterComponent, Access(typeof(MoppingSystem))]
 public sealed class AbsorbentComponent : Component
 {
     public const string SolutionName = "absorbed";

Content.Server/Fluids/Components/EvaporationComponent.cs

@@ -4,7 +4,7 @@ using Content.Shared.FixedPoint;
 namespace Content.Server.Fluids.Components
 {
     [RegisterComponent]
-    [Friend(typeof(EvaporationSystem))]
+    [Access(typeof(EvaporationSystem))]
     public sealed class EvaporationComponent : Component
     {
         /// <summary>

Content.Server/Fluids/Components/FluidSpreaderComponent.cs

@@ -4,7 +4,7 @@ using Content.Shared.Chemistry.Components;
 namespace Content.Server.Fluids.Components;
 
 [RegisterComponent]
-[Friend(typeof(FluidSpreaderSystem))]
+[Access(typeof(FluidSpreaderSystem))]
 public sealed class FluidSpreaderComponent : Component
 {
     [ViewVariables]

Content.Server/Fluids/Components/PuddleComponent.cs

@@ -8,7 +8,7 @@ namespace Content.Server.Fluids.Components
     /// Puddle on a floor
     /// </summary>
     [RegisterComponent]
-    [Friend(typeof(PuddleSystem))]
+    [Access(typeof(PuddleSystem))]
     public sealed class PuddleComponent : Component
     {
         public const string DefaultSolutionName = "puddle";

Content.Server/Fluids/Components/SprayComponent.cs

@@ -7,7 +7,7 @@ using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototy
 namespace Content.Server.Fluids.Components;
 
 [RegisterComponent]
-[Friend(typeof(SpraySystem))]
+[Access(typeof(SpraySystem))]
 public sealed class SprayComponent : Component
 {
     public const string SolutionName = "spray";
@@ -32,5 +32,6 @@ public sealed class SprayComponent : Component
     [DataField("impulse")] public float Impulse;
 
     [DataField("spraySound", required: true)]
+    [Access(typeof(SpraySystem), Other = AccessPermissions.ReadExecute)] // FIXME Friends
     public SoundSpecifier SpraySound { get; } = default!;
 }