Fix review claim event spoof

[FlacoJones]

• Add the same bountyExists check that protects against event spoofing in DepositManagerV1 to the ClaimManagerV1 methods permissionedClaimTieredBounty(address,bytes) and claimBounty(address,address,bytes)

• Adds onlyProxy to ClaimManagerV1::pause and ClaimManagerV1::unpause

• Remove codepath to call _claimTieredFixedBounty from the onlyOracle ClaimManagerV1::claimBounty method. There is no scenario where this would be needed right now, and introduced the ability to drain contracts in the event of an oracle compromise.

• Adds whenNotPaused to ClaimManagerV1::claimBounty

Closes #134

[IAm0x52]

Fixes look good. bountyExists check protects against even spoofing. claimBounty is now protected by pause. Claiming tiered bounties is now always pull rather than push or pull.