chore: fix misspelling of "dismiss" (#24951)

Fixes misspellings of "dismiss" I happened to notice from when my other typo PR (#24924) got merged.

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: ScottRobinson03

tools/@aws-cdk/prlint/lint.ts

@@ -206,7 +206,7 @@ export class PullRequestLinter {
       await this.client.pulls.dismissReview({
         ...this.prParams,
         review_id: existingReview.id,
-        message: '✅ Updated pull request passes all PRLinter validations. Dissmissing previous PRLinter review.'
+        message: '✅ Updated pull request passes all PRLinter validations. Dismissing previous PRLinter review.'
       })
     }
   }
@@ -274,7 +274,7 @@ export class PullRequestLinter {
 
   /**
    * Performs validations and communicates results via pull request comments, upon failure.
-   * This also dissmisses previous reviews so they do not remain in REQUEST_CHANGES upon fix of failures.
+   * This also dismisses previous reviews so they do not remain in REQUEST_CHANGES upon fix of failures.
    */
   public async validate(): Promise<void> {
     const number = this.props.number;