Remove handling of EVENT_UNFULFILLABLE_REQUEST

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Test: built, flashed, WiFi and telephony working
Test: atest FrameworksNetTests
Bug: 138306002
Merged-In: I5b1ec3136ae8a0a6928e0fb2cda3d5f5e2ca657f
Change-Id: I5b1ec3136ae8a0a6928e0fb2cda3d5f5e2ca657f
(clean cherry-pick from internal branch)