Limit wifi item edit content's max length to 500 Bug: 293199910 Test: manual - on "Add network" (cherry picked from commit 855053ca4124f2d515b21c469096f8c18bd4829d) (cherry picked from https://googleplex-android-review.googlesource.com/q/commit:092668676af741719d50ac0f121a8f8461aa21ad) Merged-In: I303b8c6e0f3c3a1174a047ba98f302042e5db9ae Change-Id: I303b8c6e0f3c3a1174a047ba98f302042e5db9ae