ext_proc: Remove extra spaces from proto comments causing git-push failure.

[sumitkmr2]

Commit Message: Remove extra spaces from proto comments causing git-push failure.
Additional Description: After pulling latest main, git-push started failing with this error

ERROR: From ./api/envoy/extensions/filters/http/ext_proc/v3/processing_mode.proto
ERROR: ./api/envoy/extensions/filters/http/ext_proc/v3/processing_mode.proto:125: over-enthusiastic spaces
ERROR: From ./api/envoy/service/ext_proc/v3/external_processor.proto
ERROR: ./api/envoy/service/ext_proc/v3/external_processor.proto:230: over-enthusiastic spaces
ERROR: ./api/envoy/service/ext_proc/v3/external_processor.proto:233: over-enthusiastic spaces

I've removed the culprit extra-spaces from the proto. This was possibly caused by merging #38753

Risk Level: None. Only proto comment changes.
Testing: N/A
Docs Changes: N/A
Release Notes: N/A
Platform Specific Features: N/A
[Optional Runtime guard:]
[Optional Fixes #Issue]
[Optional Fixes commit #PR or SHA]
[Optional Deprecated:]
[Optional API Considerations:]

[repokitteh-read-only]

As a reminder, PRs marked as draft will not be automatically assigned reviewers,
or be handled by maintainer-oncall triage.

Please mark your PR as ready when you want it to be reviewed!

🐱

Caused by: #42809 was opened by sumitkmr2.

see: more, trace.

[repokitteh-read-only]

CC @envoyproxy/api-shepherds: Your approval is needed for changes made to (api/envoy/|docs/root/api-docs/).
envoyproxy/api-shepherds assignee is @wbpcode
CC @envoyproxy/api-watchers: FYI only for changes made to (api/envoy/|docs/root/api-docs/).

🐱

Caused by: #42809 was opened by sumitkmr2.

see: more, trace.

[sumitkmr2]

@markdroth FYI.

[markdroth]

/lgtm api