ParsableMIMEValue - component() and subComponent() do not ensure the header is parsed
### Version

4.3.7

### Context

The `io.vertx.ext.web.impl.ParsableMIMEValue.component()` and `io.vertx.ext.web.impl.ParsableMIMEValue.subComponent()` methods do not call the `ensureHeaderProcessed()` method. As a result, these methods may return `null`.

A workaround exists: first call any other method that triggers parsing, e.g. `io.vertx.ext.web.impl.ParsableHeaderValue.value()`.

There is also `io.vertx.ext.web.impl.ParsableHeaderValue.forceParse()` but that's an implementation class, i.e. not part of the public API.

diff --git a/vertx-web/src/main/java/io/vertx/ext/web/impl/ParsableMIMEValue.java b/vertx-web/src/main/java/io/vertx/ext/web/impl/ParsableMIMEValue.java
index 01d24ed2f..dda7d80c9 100644
--- a/vertx-web/src/main/java/io/vertx/ext/web/impl/ParsableMIMEValue.java
+++ b/vertx-web/src/main/java/io/vertx/ext/web/impl/ParsableMIMEValue.java
@@ -17,11 +17,13 @@ public class ParsableMIMEValue extends ParsableHeaderValue implements MIMEHeader
 
   @Override
   public String component() {
+    ensureHeaderProcessed();
     return component;
   }
 
   @Override
   public String subComponent() {
+    ensureHeaderProcessed();
     return subComponent;
   }
 
['vertx-web/src/main/java/io/vertx/ext/web/impl/ParsableMIMEValue.java']