fixing point series chart margins

[ppisljar]

while fixing #11930 margins were broken for split charts, this resolves that issue

Resolves #12645

[thomasneirynck]

LGTM

[thomasneirynck]

Seems recent master changes in master b86f97c have broken this PR.

[weltenwort]

LGTM in regard to the the gap between the bars and the x-axis.

Since I could not reproduce the issue #12645 I can not speak to that.

[thomasneirynck]

seems to be failing on flaky dashboard test

 └- ✖ fail: "dashboard app dashboard time dashboard with stored timed sets quick time on open"
09:16:02.230        │        Error: expected 'This month' to equal 'Today'
09:16:02.230        │         at Assertion.assert (node_modules/expect.js/index.js:96:13)
09:16:02.230        │         at Assertion.be.Assertion.equal (node_modules/expect.js/index.js:216:10)
09:16:02.230        │         at Context.<anonymous> (test/functional/apps/dashboard/_dashboard_time.js:58:32)
09:16:02.230        │         at undefined.next (native)
09:16:02.230        │         at step (test/functional/apps/dashboard/_dashboard_time.js:1:1)
09:16:02.230        │         at test/functional/apps/dashboard/_dashboard_time.js:1:1
09:16:02.230        │         at process._tickDomainCallback (internal/process/next_tick.js:135:7)

jenkins, test this

[ppisljar]

backports:
5.x: 84efff0
5.5: 1185155