Re-factor expressions editor to be more generic and re-usable

[nkylstad]

Description

Expressions are used in several places in an app, f.ex:

• several different component properties
• layout (hidden property)
• texts
• process sequence flows (from gateways)

The expressions editor is currently only implemented for the components use case, and is likely a little too tied to that case.
We should extract the essentials into a new, re-usable component that takes context as input in order to be able to generate expressions in all of the above cases.

[standeren]

Came across an issue from this PR when testing something else; when filtering the component properties for Repeating Group for finding the properties that may have expressions, edit prop is not always set when searching for the subkey.
Quickfix in this PR #12435

[TomasEng]

På grunn av en feil i designsystemet kan det dukke opp noen overskrifter som egentlig ikke skal være synlige på skjermen. Dette er fikset i versjon 0.51.3 av designsystemet.

[TomasEng]

Takket være feilen nevnt over oppdaget jeg en annen feil, i en tekstreferanse. Den er fikset her: #12493

[lassopicasso]

Tested in dev - encountered two bugs while testing the functionality of expressions.
Created bug issues for these two:

• Expression Editing Crash Triggered by Deletion of Linked Components #12564
• Dropdown in "Lag en ny Logikkregel" does not close after option selection #12565