chore: remove invalid options for MeshGatewayRoute

[michaelbeaumont]

These don't need to be in the protos (yet) and shouldn't be in the generated docs. We don't need to preemptively validate that users aren't including these keys and we don't need placeholders for matches (TCP will never have any anyway).

Checklist prior to review

• Link to docs PR or issue --
• Link to UI issue or PR --
• Is the issue worked on linked? --
• The PR does not hardcode values that might break projects that depend on kuma (e.g. "kumahq" as a image registry) --
• The PR will work for both Linux and Windows, system specific functions like syscall.Mkfifo have equivalent implementation on the other OS --
• Unit Tests --
• E2E Tests --
• Manual Universal Tests --
• Manual Kubernetes Tests --
• Do you need to update UPGRADE.md? --
• Does it need to be backported according to the backporting policy? --

Changelog: chore(gateway): remove invalid options for MeshGatewayRoute

[codecov-commenter]

Codecov Report

Merging #4890 (a013e6f) into master (ae1cd10) will increase coverage by 0.11%.
The diff coverage is 6.38%.

@@            Coverage Diff             @@
##           master    #4890      +/-   ##
==========================================
+ Coverage   46.43%   46.54%   +0.11%     
==========================================
  Files         687      687              
  Lines       46913    46788     -125     
==========================================
- Hits        21783    21777       -6     
+ Misses      23219    23102     -117     
+ Partials     1911     1909       -2     

Impacted Files	Coverage Δ
...ore/resources/apis/mesh/gateway_route_validator.go	98.63% <ø> (+2.46%)	⬆️
pkg/xds/generator/ingress_generator.go	79.66% <ø> (+2.61%)	⬆️
api/mesh/v1alpha1/gateway_route.pb.go	3.77% <6.38%> (+0.21%)	⬆️
pkg/core/resources/manager/cache.go	88.31% <0.00%> (+2.59%)	⬆️

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