Added isInit flag to only calculate initial content hash when isInit is true

This helps preventing a new hash being calculated on copy/paste operations, marking the content
as NO_CHANGE when some new piece of text has just been pasted / inserted.
For context, fromHtml() was calculating the initial hash under the assumption that this method
was only being called when starting AztecText (or moving from HTML to the visual editing view,
which is the same to all effects).

Author: mzorz

aztec/src/main/kotlin/org/wordpress/aztec/AztecText.kt

@@ -1012,7 +1012,7 @@ open class AztecText : AppCompatEditText, TextWatcher, UnknownHtmlSpan.OnUnknown
         return cursorPosition
     }
 
-    open fun fromHtml(source: String) {
+    open fun fromHtml(source: String, isInit: Boolean = true) {
         val builder = SpannableStringBuilder()
         val parser = AztecParser(plugins)
 
@@ -1037,7 +1037,9 @@ open class AztecText : AppCompatEditText, TextWatcher, UnknownHtmlSpan.OnUnknown
 
         setSelection(cursorPosition)
 
-        initialEditorContentParsedSHA256 = calculateInitialHTMLSHA(toPlainHtml(false), initialEditorContentParsedSHA256)
+        if (isInit) {
+            initialEditorContentParsedSHA256 = calculateInitialHTMLSHA(toPlainHtml(false), initialEditorContentParsedSHA256)
+        }
 
         loadImages()
         loadVideos()
@@ -1400,7 +1402,7 @@ open class AztecText : AppCompatEditText, TextWatcher, UnknownHtmlSpan.OnUnknown
                 val oldHtml = toPlainHtml().replace("<aztec_cursor>", "")
                 val newHtml = oldHtml.replace(Constants.REPLACEMENT_MARKER_STRING, textToPaste + "<" + AztecCursorSpan.AZTEC_CURSOR_TAG + ">")
 
-                fromHtml(newHtml)
+                fromHtml(newHtml, false)
                 inlineFormatter.joinStyleSpans(0, length())
             }
         }