[Tests] always use legacy peer-deps on eslint-8- and node-minors matrices

The strict-peer cells (`(eslint 7, parser 6, babel-eslint *)` on
`eslint-8-`, and `(node>=16, eslint>=7)` on `node-minors`) hit a
post-`npm install` ERESOLVE at the `after_install` swap-eslint-down step,
because `eslint-config-airbnb-base@15.0.0` peers `eslint@^7.32 || ^8.2`
and `@typescript-eslint/parser@6` peers `eslint@^7 || ^8`, leaving npm
an unsatisfiable graph it sometimes lands and sometimes crashes on.

Flipping these env values to `"true"` is strictly more permissive: cells
that previously installed under strict peers still install, and the
unsatisfiable cells now install with peer warnings instead of an
ERESOLVE crash. Closes #4007.

Author: captaindonald

.github/workflows/eslint-8-.yml

@@ -102,7 +102,7 @@ jobs:
           after_install: |
             npm install --no-save "eslint@${{ matrix.eslint }}" "@typescript-eslint/parser@${{ matrix.typescript-eslint == 8 && 8.17 || matrix.typescript-eslint }}" "babel-eslint@${{ matrix.babel-eslint }}"
         env:
-          NPM_CONFIG_LEGACY_PEER_DEPS: "${{ matrix.typescript-eslint >= 6 && 'false' || 'true' }}"
+          NPM_CONFIG_LEGACY_PEER_DEPS: "true"
       - run: npx ls-engines
       - run: npm run unit-test
       - uses: codecov/codecov-action@v3.1.5

.github/workflows/node-minors.yml

@@ -106,7 +106,7 @@ jobs:
             npm install --no-save "eslint@${{ matrix.eslint }}" "@typescript-eslint/parser@${{ matrix.node-version >= 18 && matrix.eslint >= 8 && '8.17' || (matrix.node-version >= 16 && matrix.eslint >= 7 && '6' || (matrix.node-version >= 14 && '5' || (matrix.node-version >= 12 && '4' || (matrix.node-version >= 10 && '4.0' || (matrix.node-version >= 8 && '3' || '2'))))) }}" "babel-eslint@${{ matrix.babel-eslint }}"
           skip-ls-check: ${{ matrix.node-version < 10 && true || false }}
         env:
-          NPM_CONFIG_LEGACY_PEER_DEPS: "${{ matrix.node-version >= 16 && matrix.eslint >= 7 && 'false' || 'true' }}"
+          NPM_CONFIG_LEGACY_PEER_DEPS: "true"
       - run: npx ls-engines
         if: ${{ matrix.node-version >= 12 }}
       - run: npm run unit-test