contracts/ccip/capability: per (donId, pluginType) active config indexes

[makramkd]

Motivation

Using a single s_activeConfigIndex for all configurations leads to buggy outcomes (see below for an example trace).

for commit:
setCandidate(): 
    s_activeConfigIndex == 0
    candidateIndex := _getCandidateIndex(): 0 ^ 1 == 1
    s_configs[donId][pluginType][candidateIndex] = newConfig

promoteCandidate():
    s_activeConfigIndex == 0
    _getCandidateIndex(): 0 ^ 1 == 1
    s_activeConfigIndex ^= 1; => s_activeConfigIndex == 1

call getActiveDigest(): s_configs[donId][pluginType][1].configDigest returns correct digest

for exec:
setCandidate():
    s_activeConfigIndex == 1
    candidateIndex := _getCandidateIndex(): 1 ^ 1 == 0
    s_configs[donId][pluginType][candidateIndex] = newConfig

promoteCandidate(): 
    s_activeConfigIndex == 1
    _getCandidateIndex(): 1 ^ 1 == 0
    s_activeConfigIndex ^= 1; => s_activeConfigIndex == 0

call getActiveDigest(donId, commit):
    // commit's active is at index 1 (see above)
    // but since s_activeConfigIndex is set to zero, we access the array at 0
    // but this config is empty because it gets deleted in commit promoteCandidate
    s_configs[donId][commit][0].configDigest // 0x0 digest

Solution

Make s_activeConfigIndex per-donId per-plugin instead.

[github-actions]

LCOV of commit 48bb4fc during Solidity Foundry #8518

Summary coverage rate:
  lines......: 97.8% (2263 of 2313 lines)
  functions..: 95.3% (426 of 447 functions)
  branches...: 93.6% (537 of 574 branches)

Files changed coverage rate: n/a

[cl-sonarqube-production]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
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