Separate OTABackend from OTA component (#6459)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/__main__.py

@@ -18,22 +18,23 @@ from esphome.const import (
     CONF_BAUD_RATE,
     CONF_BROKER,
     CONF_DEASSERT_RTS_DTR,
+    CONF_DISABLED,
+    CONF_ESPHOME,
     CONF_LOGGER,
+    CONF_MDNS,
+    CONF_MQTT,
     CONF_NAME,
     CONF_OTA,
-    CONF_MQTT,
-    CONF_MDNS,
-    CONF_DISABLED,
     CONF_PASSWORD,
-    CONF_PORT,
-    CONF_ESPHOME,
+    CONF_PLATFORM,
     CONF_PLATFORMIO_OPTIONS,
+    CONF_PORT,
     CONF_SUBSTITUTIONS,
     PLATFORM_BK72XX,
-    PLATFORM_RTL87XX,
     PLATFORM_ESP32,
     PLATFORM_ESP8266,
     PLATFORM_RP2040,
+    PLATFORM_RTL87XX,
     SECRETS_FILES,
 )
 from esphome.core import CORE, EsphomeError, coroutine
@@ -330,15 +331,19 @@ def upload_program(config, args, host):
 
         return 1  # Unknown target platform
 
-    if CONF_OTA not in config:
+    ota_conf = {}
+    for ota_item in config.get(CONF_OTA, []):
+        if ota_item[CONF_PLATFORM] == CONF_ESPHOME:
+            ota_conf = ota_item
+            break
+
+    if not ota_conf:
         raise EsphomeError(
-            "Cannot upload Over the Air as the config does not include the ota: "
-            "component"
+            f"Cannot upload Over the Air as the {CONF_OTA} configuration is not present or does not include {CONF_PLATFORM}: {CONF_ESPHOME}"
         )
 
     from esphome import espota2
 
-    ota_conf = config[CONF_OTA]
     remote_port = ota_conf[CONF_PORT]
     password = ota_conf.get(CONF_PASSWORD, "")