add missing env variables for proxy file

[DenysVuika]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x")

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation
• Other... Please describe:

What is the current behaviour? (You can also link to an open issue here)

What is the new behaviour?

add the missing call to load env file in the proxy

Does this PR introduce a breaking change? (check one with "x")

• Yes
• No

If this PR contains a breaking change, please describe the impact and migration path for existing applications: ...

Other information:

[codecov-io]

Codecov Report

Merging #6319 into develop will increase coverage by 1.12%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #6319      +/-   ##
===========================================
+ Coverage    76.24%   77.37%   +1.12%     
===========================================
  Files          865      148     -717     
  Lines        19582     4146   -15436     
  Branches      3889      825    -3064     
===========================================
- Hits         14931     3208   -11723     
+ Misses        3484      664    -2820     
+ Partials      1167      274     -893     

Impacted Files	Coverage Δ
...dgets/dynamic-table/number-cell-validator.model.ts
...re/form/events/validate-dynamic-table-row.event.ts
...l/icons/raphael-icon-alfresco-publish.component.ts
lib/core/info-drawer/info-drawer.module.ts
...aphael/icons/raphael-icon-box-publish.component.ts
...ble/directives/header-filter-template.directive.ts
lib/core/clipboard/clipboard.service.ts
...le/directives/custom-loading-template.directive.ts
lib/core/dialogs/edit-json/edit-json.dialog.ts
...m/components/widgets/hyperlink/hyperlink.widget.ts
... and 707 more

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