[aapt2] dump badging: rename sdkVersion to minSdkVersion

`aapt2 dump badging` will label the minSdkVersion as "sdkVersion". This
is inconsistent with the labels for targetSdkVersion and maxSdkVersion,
which include the target/max prefixes.

Change the label of of minSdkVersion from "sdkVersion" to
"minSdkVersion" to reduce the risk of confusion.

Bug: 292216817
Test: atest aapt2_tests
Test: aapt2 dump badging <path-to-apk> # manually inspect output, compare with aapt2 dump xmltree --file AndroidManifest.xml <path-to-apk>
Change-Id: Ic9f74636ecd1daa67f62bd8839f7ce095f351ad5