[Spring] Remove unnecessary modifiers from API interface templates

[daberni]

In the api.mustache file of Spring generator, for the newly introduced endpoint_PATH constants, unnecessary specific modifiers are specified (public, static, final)

Those modifiers do apply on properties inside of interfaces automatically.

Modifier 'public' is redundant for interface members
Modifier 'static' is redundant for interface fields
Modifier 'final' is redundant for interface fields

This change gets rid of these modifiers, with no further impact on the compiled code.

@cachescrubber @welshm @MelleD @atextor @manedev79 @javisst @borsch @banlevente @Zomzog @martin-mfg

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[wing328]

thanks for the pr

can you please merge the latest master into your branch?

we've fixed a couple of ci issues in the latest master

[daberni]

@wing328 done, and build checks look good too now 👍