feat: Add email exists query

[pgbsl]

Description of changes...

This fixes/resolves/relates to Jira ticket: [FCPDAL-xxx]

[github-actions]

Coverage report

Caution

Test run failed

St.❔	Category	Percentage	Covered / Total
🟢	Statements	98.88% (+0.01% 🔼)	886/896
🟢	Branches	96.32%	340/353
🟢	Functions	99.65% (+0% 🔼)	287/288
🟢	Lines	98.85% (+0.01% 🔼)	863/873

Test suite run failed

Failed tests: 2/421. Failed suites: 1/58.

  ● schema › should contain all fields if process.env.ALL_SCHEMA is set

    expect(received).toHaveLength(expected)

    Expected length: 0
    Received length: 1
    Received array:  [{"description": "Query.customerEmail changed type from Boolean to CustomerEmail.", "type": "FIELD_CHANGED_KIND"}]

      150 |
      151 |     expect(findDangerousChanges(fullSchema, schema)).toHaveLength(0)
    > 152 |     expect(findBreakingChanges(fullSchema, schema)).toHaveLength(0)
          |                                                     ^
      153 |     expect(findDangerousChanges(schema, fullSchema)).toHaveLength(0)
      154 |     expect(findBreakingChanges(schema, fullSchema)).toHaveLength(0)
      155 |   })

      at Object.toHaveLength (test/graphql/schema.test.js:152:53)

  ● schema › should only contain fields that have the directive

    expect(received).toHaveLength(expected)

    Expected length: 0
    Received length: 1
    Received array:  [{"description": "Query.customerEmail was removed.", "type": "FIELD_REMOVED"}]

      162 |
      163 |     expect(findDangerousChanges(partialSchema, schema)).toHaveLength(0)
    > 164 |     expect(findBreakingChanges(partialSchema, schema)).toHaveLength(0)
          |                                                        ^
      165 |     expect(findDangerousChanges(schema, partialSchema)).toHaveLength(0)
      166 |     expect(findBreakingChanges(schema, partialSchema)).toHaveLength(0)
      167 |   })

      at Object.toHaveLength (test/graphql/schema.test.js:164:56)

Report generated by 🧪jest coverage report action from f94e157