Fix last letter missing in ViewTraversalTracingStrings

The end inx was excluded already by String#substring, so no need for -1.

Fixes: 324879474
Test: Perfetto trace with debug relayout enabled (adb shell setprop persist.debug.trace_layouts 1)
Flag: None
Change-Id: I8ba9f77a6ea85e35b272ef1633bb8e0a72bee146