Add sendHint method to the PowerHintSession API for load changes

Add a new sendHint(SessionHint hint) method to the PowerHintSession to
allow clients to inform the session about upcoming changes in load ahead
of time.

Bug: b/243973548
Test: atest VtsHalPowerTargetTest
Change-Id: I0a8af42d3b0ccd3bbb72287a9b91ffb13fccaf9c
diff --git a/power/aidl/default/power-default.xml b/power/aidl/default/power-default.xml
index 927ba22..f5dd6b9 100644
--- a/power/aidl/default/power-default.xml
+++ b/power/aidl/default/power-default.xml
@@ -1,7 +1,7 @@
 <manifest version="1.0" type="device">
     <hal format="aidl">
         <name>android.hardware.power</name>
-        <version>3</version>
+        <version>4</version>
         <fqname>IPower/default</fqname>
     </hal>
 </manifest>