[AAE-3219] Start process button is disabled when page is first displayed

[mcchrys]

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)
https://issues.alfresco.com/jira/browse/AAE-3219

The generateProcessInstance() is called before the default processInstanceName is set.

What is the new behaviour?

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-commenter]

Codecov Report

Merging #5955 into develop will increase coverage by 2.32%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #5955      +/-   ##
===========================================
+ Coverage    76.08%   78.40%   +2.32%     
===========================================
  Files          843      334     -509     
  Lines        18764     8947    -9817     
  Branches      3690     1779    -1911     
===========================================
- Hits         14276     7015    -7261     
+ Misses        3374     1384    -1990     
+ Partials      1114      548     -566     

Impacted Files	Coverage Δ
...rocess/components/start-process-cloud.component.ts	85.29% <ø> (+4.41%)	⬆️
...ib/document-list/services/document-list.service.ts	74.50% <0.00%> (-1.97%)	⬇️
.../form/components/widgets/content/content.widget.ts
.../core/dialogs/edit-json/edit-json.dialog.module.ts
lib/core/services/comment-content.service.ts
lib/core/pipes/multi-value.pipe.ts
lib/core/services/download.service.ts
...ts/src/lib/diagram/models/chart/pie-chart.model.ts
.../form/components/widgets/unknown/unknown.widget.ts
lib/core/directives/directive.module.ts
... and 507 more

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