Order LogLevel enum values

This CL orders the LogLevel enum values by increasing severity. This
ordering is needed by ProtoLog to determine from which log level to
start logging. The ordinal value is used to compare the level values and
from which one to start logging.

Test: atest com.android.internal.protolog.ProcessedPerfettoProtoLogImplTest
Flag: TEST_ONLY
Bug: 390585237
Change-Id: I0f1195ee9e808fe1976e4a7d69dbdeff1454f7db