docs(changelog): add #1546 fragment

changelog.d/1546-chat-provider-switch.md

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+- Keep typed chat's view when switching AI Provider: Settings opened from
+  chat, or chat itself, stay as they were for the new provider instead of
+  falling back to voice and widening the dock. Opening chat or closing the
+  voice panel now also clears a voice error left on the dock (Manjunath,
+  @manjunath22466, #1546).