refactor: Simplify REPLACEMENT_GLYPH fallback (#1119)

## Summary

**What is the goal of this PR?**

Consolidated repeated logic to fall back to REPLACEMENT_GLYPH.

---

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lib/EpdFont/EpdFont.cpp

@@ -25,11 +25,6 @@ void EpdFont::getTextBounds(const char* string, const int startX, const int star
   uint32_t cp;
   while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&string)))) {
     const EpdGlyph* glyph = getGlyph(cp);
-
-    if (!glyph) {
-      glyph = getGlyph(REPLACEMENT_GLYPH);
-    }
-
     if (!glyph) {
       // TODO: Better handle this?
       continue;
@@ -95,6 +90,8 @@ const EpdGlyph* EpdFont::getGlyph(const uint32_t cp) const {
       return &data->glyph[interval->offset + (cp - interval->first)];
     }
   }
-
+  if (cp != REPLACEMENT_GLYPH) {
+    return getGlyph(REPLACEMENT_GLYPH);
+  }
   return nullptr;
 }