[esp32] Consolidate network/coexistence sdkconfig into a single reconciler (#17008)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/component_tests/esp32/config/network_ethernet_only.yaml

@@ -0,0 +1,17 @@
+esphome:
+  name: test
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+ethernet:
+  type: W5500
+  clk_pin: 19
+  mosi_pin: 21
+  miso_pin: 23
+  cs_pin: 18
+  interrupt_pin: 36
+  reset_pin: 22
+  clock_speed: 10Mhz

tests/component_tests/esp32/config/network_wifi_ble_coexistence.yaml

@@ -0,0 +1,14 @@
+esphome:
+  name: test
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+wifi:
+  ssid: "test_ssid"
+  password: "test_password"
+
+esp32_ble_tracker:
+  software_coexistence: true

tests/component_tests/esp32/config/network_wifi_only.yaml

@@ -0,0 +1,11 @@
+esphome:
+  name: test
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+wifi:
+  ssid: "test_ssid"
+  password: "test_password"