test: add api test for flash flood, dengue, and malaria

[gulfaraz]

Describe your changes

resolves #1517

Checklist before requesting a review

• I have performed a self-review of my code
• I have added tests wherever relevant
• I have made sure that all automated checks pass before requesting a review

[gulfaraz]

> test:api:all
> node --expose-gc node_modules/.bin/jest --config=jest.api.config.js --runInBand --detectOpenHandles --logHeapUsage

ts-jest[versions] (WARN) Version 4.9.5 of typescript installed has not been tested with ts-jest. If you're experiencing issues, consider using a supported version (>=2.7.0 <4.0.0). Please do not report issues in ts-jest if you are using unsupported versions.
 PASS  test/email/floods/email-ssd-floods.test.ts (15.514s, 80 MB heap size)
  Should send an email for ssd floods
    ✓ default (6615ms)
    ✓ no-trigger (8359ms)

 PASS  test/email/floods/email-uga-floods.test.ts (40.177s, 81 MB heap size)
  Should send an email for uga floods
    ✓ default (9006ms)
    ✓ warning (9287ms)
    ✓ warning-to-trigger (10270ms)
    ✓ no-trigger (11493ms)

 PASS  test/email/malaria/email-eth-malaria.test.ts (27.393s, 90 MB heap size)
  Should send an email for eth malaria
    ✓ default (13231ms)
    ✓ no-trigger (14023ms)

 PASS  test/email/dengue/email-phl-dengue.test.ts (28.252s, 81 MB heap size)
  Should send an email for phl dengue
    ✓ default (13924ms)
    ✓ no-trigger (14107ms)

 PASS  test/email/flash-flood/email-mwi-flash-flood.test.ts (64.567s, 81 MB heap size)
  Should send an email for mwi flash flood
    ✓ default (21222ms)
    ✓ no-trigger (43166ms)

 PASS  test/email/drought/email-uga-drought.test.ts (26.187s, 81 MB heap size)
  Should send an email for uga drought
    ✓ triggered in january (12144ms)
    ✓ non triggered any month (13882ms)

 PASS  test/email/typhoon/email-phl-typhoon.test.ts (17.567s, 88 MB heap size)
  Should send an email for phl typhoon
    ✓ default (17368ms)

Test Suites: 7 passed, 7 total
Tests:       15 passed, 15 total
Snapshots:   0 total
Time:        220.27s, estimated 262s
Ran all test suites.