feat: Add 'slowTestThreshold' and fix this.slow() inside specs (#18496)

Co-authored-by: Chris Breiding <chrisbreiding@users.noreply.github.com>

cli/types/cypress-npm-api.d.ts

@@ -91,6 +91,10 @@ declare namespace CypressCommandLine {
      * Specify mocha reporter options
      */
     reporterOptions: any
+    /**
+     * Slow test threshold in milliseconds. Only affects the visual output of some reporters. For example, the spec reporter will display the test time in yellow if over the threshold.
+     */
+    slowTestThreshold: number
     /**
      * Specify the specs to run
      */

cli/types/cypress.d.ts

@@ -2577,6 +2577,11 @@ declare namespace Cypress {
      * @default "spec"
      */
     reporterOptions: { [key: string]: any }
+    /**
+     * Slow test threshold in milliseconds. Only affects the visual output of some reporters. For example, the spec reporter will display the test time in yellow if over the threshold.
+     * @default 10000
+     */
+    slowTestThreshold: number
     /**
      * Whether Cypress will watch and restart tests on test file changes
      * @default true