[TP] - Parse clone snapshot trigger packet and add first trigger to the metadata

* Create a new metadata field for trace trigger that determines what triggered the trace whether it was a clone snapshot trigger or normal trigger
* Set the metadata field based on the packet type (clone snapshot takes priority then the first trace trigger packet) as the packets are already ordered by timestamp in this context
* Parse the clone snapshot trigger and add it to the trace triggers track

Bug: 345762203
Test: `tools/ninja -C out/linux_clang_debug  &&  tools/diff_test_trace_processor.py out/linux_clang_debug/trace_processor_shell --name-filter ".*Parsing.*trigger.*"`

Change-Id: I7aa88855db82a9946057454cd5b25db017687b54