Percentage mode showing normal mode as stacked (stacked is shown the same way)

[Dxnam]

**Kibana version: 7.4.0

**Elasticsearch version: 7.4

**Server OS version: Windows 10

**Browser version: Chrome lates

Browser OS version:

**Original install method (e.g. download page, yum, from source, etc.): ELK stack source page

**Describe the bug: Percentage mode showing normal mode as stacked

Steps to reproduce:

1. I am indexing from my logstash builds in form of Count as metrics
2. I am setting my Y-axis metrics with aggregation Count and my X-axis to date Histogram with Timestamp field
3. I am setting my Metrics mode to normal and Y-axis mode to percentage

**Expected behavior: The builds should be showing lines in normal, NOT STACKED mode, per each day

Screenshots (if relevant):
Metrics mode in normal and Y-axes in normal, it shows the data as expected(picture 1).

Metrics mode in stacked and Y-axes in normal, it shows the data in stacked normal as expected (picture2)

The issue is with percentage mode when both stacked and normal metrics mode show stacked data as shown in picture 3 and I need to show it in normal mode where data per each day are gonna add up to 100%

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):

Any additional context:

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[stratoula]

This was closed here #96203
We decided to allow only stacked for percentage mode