Handle 0 gas limit

apps/block_scout_web/lib/block_scout_web/views/api/v2/block_view.ex

@@ -85,13 +85,21 @@ defmodule BlockScoutWeb.API.V2.BlockView do
   end
 
   def gas_target(block) do
+    if Decimal.compare(block.gas_limit, 0) == :gt do
       elasticity_multiplier = Application.get_env(:explorer, :elasticity_multiplier)
       ratio = Decimal.div(block.gas_used, Decimal.div(block.gas_limit, elasticity_multiplier))
       ratio |> Decimal.sub(1) |> Decimal.mult(100) |> Decimal.to_float()
+    else
+      Decimal.new(0)
+    end
   end
 
   def gas_used_percentage(block) do
+    if Decimal.compare(block.gas_limit, 0) == :gt do
       block.gas_used |> Decimal.div(block.gas_limit) |> Decimal.mult(100) |> Decimal.to_float()
+    else
+      Decimal.new(0)
+    end
   end
 
   def burnt_fees_percentage(_, %Decimal{coef: 0}), do: nil