thread view: Add a few UI tweaks (#36845)

Release Notes:

- N/A

assets/icons/copy.svg

@@ -1 +1,4 @@
-<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="none"><path stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="1.2" d="M12.286 6H7.048C6.469 6 6 6.469 6 7.048v5.238c0 .578.469 1.047 1.048 1.047h5.238c.578 0 1.047-.469 1.047-1.047V7.048c0-.579-.469-1.048-1.047-1.048Z"/><path stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="1.2" d="M3.714 10a1.05 1.05 0 0 1-1.047-1.048V3.714a1.05 1.05 0 0 1 1.047-1.047h5.238A1.05 1.05 0 0 1 10 3.714"/></svg>
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M12.486 6.2H7.24795C6.66895 6.2 6.19995 6.669 6.19995 7.248V12.486C6.19995 13.064 6.66895 13.533 7.24795 13.533H12.486C13.064 13.533 13.533 13.064 13.533 12.486V7.248C13.533 6.669 13.064 6.2 12.486 6.2Z" stroke="black" stroke-width="1.2" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M3.91712 10.203C3.63951 10.2022 3.37351 10.0915 3.1773 9.89511C2.98109 9.69872 2.87064 9.43261 2.87012 9.155V3.917C2.87091 3.63956 2.98147 3.37371 3.17765 3.17753C3.37383 2.98135 3.63968 2.87079 3.91712 2.87H9.15512C9.43273 2.87053 9.69883 2.98097 9.89523 3.17718C10.0916 3.37339 10.2023 3.63939 10.2031 3.917" stroke="black" stroke-width="1.2" stroke-linecap="round" stroke-linejoin="round"/>
+</svg>