fix(text-block-view): update text listener registration and text pars…

…ing for assistant messages

Previously, the text listener was being added to the `getBlock()` which was causing issues during garbage collection. This commit updates the text listener registration to use `block` directly, ensuring that the listener is properly attached to the correct MessageBlock instance. Additionally, the text parsing for assistant messages has been moved inside the if statement where the role of the message is checked, to prevent unnecessary string conversions.

src/233/main/kotlin/com/intellij/temporary/gui/block/TextBlockView.kt

@@ -32,8 +32,8 @@ class TextBlockView(private val block: MessageBlock) : MessageBlockView {
             editorPane.invalidate()
         }
 
-        getBlock().addTextListener(messagePartTextListener)
-        messagePartTextListener.onTextChanged(getBlock().getTextContent())
+        block.addTextListener(messagePartTextListener)
+        messagePartTextListener.onTextChanged(block.getTextContent())
     }
 
     override fun getBlock(): MessageBlock = block
@@ -56,7 +56,7 @@ class TextBlockView(private val block: MessageBlock) : MessageBlockView {
     }
 
     private fun parseText(txt: String): String {
-        if (getBlock().getMessage().getRole() === ChatRole.Assistant) {
+        if (block.getMessage().getRole() === ChatRole.Assistant) {
             return convertMarkdownToHtml(txt)
         }