Trim any long string inputs that come in to AutomaticZenRule

This change both prevents any rules from being unable to be written to disk and also avoids risk of running out of memory while handling all the zen rules.

Bug: 242703460
Bug: 242703505
Bug: 242703780
Bug: 242704043
Bug: 243794204
Test: cts AutomaticZenRuleTest; atest android.app.AutomaticZenRuleTest; manually confirmed each exploit example either saves the rule successfully with a truncated string (in the case of name & conditionId) or may fail to save the rule at all (if the owner/configactivity is invalid). Additionally ran the memory-exhausting PoC without device crashes.

Change-Id: I110172a43f28528dd274b3b346eb29c3796ff2c6