[epaper_spi] Refactoring (#11540)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

tests/components/epaper_spi/test.esp32-s3-idf.yaml

@@ -4,7 +4,10 @@ packages:
 display:
   - platform: epaper_spi
     spi_id: spi_bus
-    model: 7.3in-spectra-e6
+    model: spectra-e6
+    dimensions:
+      width: 800
+      height: 480
     cs_pin: GPIO5
     dc_pin: GPIO17
     reset_pin: GPIO16
@@ -13,3 +16,6 @@ display:
     update_interval: 60s
     lambda: |-
       it.circle(64, 64, 50, Color::BLACK);
+
+  - platform: epaper_spi
+    model: seeed-reterminal-e1002