Remove OPBL message now that cleanflight releases no-longer include OPBL

compatible binaries.

_locales/en/messages.json

@@ -1152,7 +1152,7 @@
         "message": "Warning"
     },
     "firmwareFlasherWarningText": {
-        "message": "Please do <span style=\"color: red\">not</span> try to flash <strong>non-cleanflight</strong> hardware with this firmware flasher.<br />Do <span style=\"color: red\">not</span> <strong>disconnect</strong> the board or <strong>turn off</strong> your computer while flashing.<br /><br /><strong>Note: </strong>STM32 bootloader is stored in ROM, it cannot be bricked.<br /><strong>Note: </strong><span style=\"color: red\">Auto-Connect</span> is always disabled while you are inside firmware flasher.<br /><strong>Note: </strong>Make sure you have a backup; some upgrades/downgrades will wipe your configuration.<br /><strong>Note:</strong> If you have problems flashing try disconnecting all cables from your FC.<br /><br /><strong>Note: </strong>If you have lost comminication with your board then power off the board, jumper the bootloader pins, power on, enable 'No reboot sequence', enable 'Full chip erase', re-flash, then power off, remove bootloader jumper, power on and connect (For all firmware except OPBL firmware)."
+        "message": "Please do <span style=\"color: red\">not</span> try to flash <strong>non-cleanflight</strong> hardware with this firmware flasher.<br />Do <span style=\"color: red\">not</span> <strong>disconnect</strong> the board or <strong>turn off</strong> your computer while flashing.<br /><br /><strong>Note: </strong>STM32 bootloader is stored in ROM, it cannot be bricked.<br /><strong>Note: </strong><span style=\"color: red\">Auto-Connect</span> is always disabled while you are inside firmware flasher.<br /><strong>Note: </strong>Make sure you have a backup; some upgrades/downgrades will wipe your configuration.<br /><strong>Note:</strong> If you have problems flashing try disconnecting all cables from your FC.<br /><br /><strong>Note: </strong>If you have lost comminication with your board then power off the board, jumper the bootloader pins, power on, enable 'No reboot sequence', enable 'Full chip erase', re-flash, then power off, remove bootloader jumper, power on and connect."
     },
     "firmwareFlasherButtonLeave": {
         "message": "Leave Firmware Flasher"