fix: attempt to display Blob response bodies as text (#4437)

* fix: attempt to display Blob response bodies as text

... if nothing else works.

* correctly pass `prevProps.content` to updateParsedContent

* remove debugger statement

* caniuse `Blob` && `FileReader`? yes.

Blob: https://caniuse.com/#search=Blob
FileReader: https://caniuse.com/#search=filereader

src/style/_layout.scss

@@ -632,6 +632,7 @@
   > .microlight {
     overflow-y: auto;
     max-height: 400px;
+    min-height: 6em;
   }
 }